With the Buffalo Bills and Kansas City Chiefs set to meet for the fifth time in the last three seasons, there's no shortage of storylines. This specific breakdown won't detail too much of what's to be expected Sunday afternoon, but instead focus on why Bills-Chiefs has turned into the premier NFL matchup.

The answer lies in star quarterbacks, a coaching chess match and the race for Super Bowl trophies.

Manning vs. Brady 2.0

It'd be nearly impossible to describe an ideal NFL matchup at any point in history without mentioning each team's quarterbacks at the top of the list. And if we're talking best QB matchups of all-time, the gold standard is Tom Brady vs. Peyton Manning who met 17 total times across 15 seasons, including the playoffs.

Over the last two years — and especially after the two duels in Kansas City last season — no other QB matchup in the NFL as quickly ascended into the Manning-Brady stratosphere as the conversation surrounding Allen-Mahomes has.

"It's such a weird feeling. I don't really take steps back and look at it from that lens too often," Allen shared this week on Kyle Brandt’s Basement podcast. "But to know as a kid, I remember watching Peyton and Tom and then Tom and Aaron and to know people regard me in that situation, it's surreal."

The career trajectory similarities between Manning-Brady and Allen-Mahomes are, in some ways, uncanny. There's also plenty that distinguishes the two matchups from each other.

To fit into the category of a perennial elite NFL matchup, not only do the QBs have to be great themselves, but the team around them must also be great. 

"They are two premier organizations," NFL Network analyst Brian Baldinger said this week about the Bills and Chiefs on the One Bills Live podcast.

The Chiefs are an astounding 53-14 in regular season games with Mahomes at QB since he became the full-time starter in 2018. They are 8-3 with him in the postseason, including a Super Bowl LIV championship and four straight trips to the AFC Championship Game. 

Brady's Patriots charted a similar path early in his career, winning 3 Super Bowls in his first 5 seasons, and posting a 58-20 record with Brady as the starter during that span.

Like Brady, Mahomes had the benefit of sitting much of his first season and learning under then-Chiefs QB Alex Smith. 

For Allen, when he was taken with the 7th overall pick in the 2018 Draft, he became Buffalo's full-time starter as soon as the second week of his rookie season. Allen had the pressure of turning around an organization who had suffered through a long playoff drought, much like Manning dealt with in his arrival in Indianapolis.  

"I think you're seeing the trajectory for Allen be more like what those guys were, particularly Peyton," CBS Sports senior writer Pete Prisco said this week. 

In his first season, Allen threw 12 INTs in 11 starts, posting a 5-6 record. In Peyton's first season in 1998, he went 3-13 with an NFL record 28 INTs. It wasn't until their second season that each QB broke through and led their respective teams to playoff berths. 

Allen — along with help from head coach Sean McDermott and GM Brandon Beane (more on McDermott later) — has successfully flipped the script for the Bills franchise, taking the team from cellar dwellers to Super Bowl contenders. 

Now, Allen holds a career record of 43-22, including 3-straight winning seasons, and just passed Peyton Manning last weekend for fourth all-time in most touchdowns in a player's first five NFL seasons. 

This isn't to suggest that Mahomes' career will become like Brady's or Allen's into Manning's. Rather to show that even though it may seem hyperbole to put Allen-Mahomes meetings in the same category as two all-time greats, there's more than one reason to believe it's closer to reality than a myth.

But where you see them add an element Manning-Brady matchups never had is their ability to impact the game with their legs.

"I think their mobility is better than both of those guys early in their career," Prisco said.

Coaching respect

It's no secret to anyone familiar with either side that Bills coach Sean McDermott and Chiefs coach Andy Reid share a great deal of respect for one another, with McDermott on the Eagles' coaching staff with Reid for a decade.

"It's fascinating in some ways, right?" McDermott said. "Because of where I got my start, who I learned a lot from No. 1, that's certainly one chapter of the book of this story. But then you fast forward to moving beyond that now and my sixth year coaching here. And the quarterback that we have and the quarterback that they have is another chapter of the story."

While Reid has coached in over 400 NFL games, McDermott is still young by NFL coaches standards, only in his sixth season. That makes it all the more impressive that McDermott passed Bills Legend and Pro Football Hall of Famer Marv Levy in Buffalo Bills career winning percentage (.616) last weekend with the team's 38-3 win over the Steelers. 

"I think Sean's evolved from an offensive standpoint, which I think is smart coaching," Prisco said. "That's what makes a really good coach is a guy who can look at what he thinks it should be, and then realize what it should be isn't what he thinks it should be, but rather what they do for the best of the team and that's why Sean's a darn good coach."

McDermott shared that it's a great challenge to prepare for a team like the Chiefs, especially in the high-leverage opportunities where the two teams have met.

"Just the games that we've played and how both organizations have been so successful for now couple of years, at least for us overlapping them. They've been at it a little longer than we have," McDermott said. 

That respect is something that transcends beyond the coaches. Allen and Mahomes, too, are friends. The two often speak highly of each other and even played in The Match together over the summer against Tom Brady and Aaron Rodgers.

"Josh is a great guy. He's a great quarterback — physically talented, he can throw, can run, he can really do it all," Mahomes told the Kansas City media this week. "But he's a great dude too. And so, obviously when we're on the football field, we are competing against each other and we want to beat each other's teams, but I have a ton of respect for him, the player and person that he is."

That mutual admiration on both sides keeps bad blood from spilling over. While both teams will want to avenge a loss from the previous matchup, it rarely boils over into dirty plays or cheap shots.

"I think there is a lot of respect between both programs," McDermott said.

See you in January

But the similarities between Brady-Manning and Allen-Mahomes, along with the high regard of both franchises doesn't make a compelling series year after year if their duels fizzle out or have little impact on the stakes of the season.

The opposite rings true in fact, as two of their last three meetings have come in the AFC Playoffs. A 38-20 win by the Bills in primetime of Week 5 last season is sandwiched by the Chiefs taking the conference championship in 2020 and the divisional round in 2022.

That is at the heart of why Allen vs. Mahomes & Bills vs. Chiefs carries so much weight: they are likely to be standing in each other's way for a championship for years to come. 

"They're just scratching the surface of what they can be for the long term," Prisco said. 

"What they have done in Buffalo, is what every team trying to find some footing is trying to emulate," Baldinger said. "And Kansas City with Andy Reid and the Hunt family, they've got that down. They're two elite franchises."

Kansas City had a five-decade drought between Super Bowl wins; the Bills have never won a Super Bowl. Now, it's more than likely one or both of them will be positioned to win it all for years to come.

That means more high-stakes, bite-your-finger-nails Bills-Chiefs games are on the horizon, even after Week 6.