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A rematch some seven years in the making -- this time for the welterweight title -- will headline UFC 278 on Saturday from Salt Lake City, Utah.  

Pound-for-pound king Kamaru Usman will look for the sixth defense of his 170-pound title when he welcomes top contender Leon Edwards, whom he first defeated by unanimous decision in 2015. The card will also feature a must-see bantamweight attraction and the return of former middleweight champion Luke Rockhold, who hasn't recorded a win since 2017.   

Let's take a closer look at the biggest storylines entering this weekend's pay-per-view card.  

1. The more things change, the more they stay the same 

It's easy to dismiss the results of the first meeting between these top welterweights considering it happened so long ago. Usman was making his first walk to the Octagon since winning "The Ultimate Fighter" in his official UFC debut five months earlier. Edwards, meanwhile, was looking merely to make a name for himself in his fourth UFC appearance, which explains why their first bout took place nearly out of site and mind on the early prelims. Both fighters are a combined 22-0 (1 NC) since their first fight, which suggests how much each fighter has evolved in the aftermath. While that's certainly true (and hard to argue considering Usman was almost exclusively a wrestler in those days), the challenge for Edwards pretty much remains the same. Usman found success pressuring Edwards behind the threat of the takedown. Even with his evolved striking game, the foundational aspects of a potential victory in their rematch remain the same for the champion. For all the improvements Edwards has made throughout a painfully long march toward his first title shot, the challenge of Usman remains just as daunting the second time around.

2. It's getting harder and harder to deny Usman entry into the G.O.A.T. debate 

Too many podcast hours to fill each week has made discussions regarding who are the greatest fighters in MMA history at any given moment a constant source of regurgitated material. Yet the general consensus remains that if there is a mythical "upper room" containing those with at least a stake in the larger G.O.A.T. discussion, it likely consists of some variation of Jon Jones, Anderson Silva, Georges St-Pierre, Demetrious Johnson, Fedor Emelianenko and Khabib Nurmagomedov, depending upon your preference. Has Usman, 35, done enough just yet to warrant inclusion? The truth is he's getting closer and closer. If Usman's 20-1 overall record isn't glossy enough (his lone career defeat came in his second pro fight in 2013), the native of Nigeria is riding an absurd 19-fight win streak into the Edwards rematch. A victory would tie him with Anderson Silva for the UFC record of consecutive wins while bringing Usman within three title defenses of equaling GSP's mark at of nine at welterweight. But the best argument in favor of the current P4P king would surround just how dominant he has been throughout the streak. The only UFC opponent to give Usman legitimate trouble was Colby Covington, and Usman defeated him twice. Usman would likely need a follow-up victory after Edwards against the rising Khamzat Chimaev to fully get his due in this category, but his success largely speaks for itself.  

3. At 37, Luke Rockhold's fighting future hangs in the balance 

The fallout of Rockhold's 2016 upset title loss to Michael Bisping in their rematch hasn't been kind. Including the loss, the former 185-pound king is just 1-3 since taking the title from Chris Weidman at UFC 194 and all three losses have come via knockout (including a failed bid at light heavyweight). Rockhold returns against the dangerous yet mercurial Paulo Costa in a pairing that offers equal potential for big reward or a disastrous result. Rockhold has gone public saying he believes his name value would merit getting a title shot should he defeat Costa and said he would accept no alternative from UFC matchmakers. Just the same, it wouldn't be out of the question to see a loss end -- and, in particular, a knockout defeat -- end Rockhold's time with the UFC altogether. Yes, Rockhold's chin has betrayed him in each of his three high-profile losses in recent years, but the larger problem has seemed to be the careless arrogance he often shows around dangerous opponents. Costa has been erratic since coming up short in his title bid against Israel Adesanya but remains a dangerous threat to end the fight -- and possibly Rockhold's career -- at any given point.  

4. Jose Aldo isn't done finding out how great he can be 

At 35 and having already moved down in weight to join arguably the deepest field in any given division at any point in MMA history, the idea of Aldo securing yet another UFC title shot sounds like the plot of a movie. Aldo, the longtime featherweight king who lost a vacant title bout in 2020 at 135 pounds to Petr Yan, seemingly surprised everyone by recording a trio of decision wins in the aftermath against accomplished contenders Marlon Vera, Pedro Munhoz and Rob Font. On Saturday, the task only gets harder for the "King of Rio" when he enters as a slight underdog against the red-hot Merab Dvalishvilli, who is riding a seven-fight win streak. The possibility of rising star Sean O'Malley earning a title shot should he defeat Yan at UFC 280 remains strong given his popularity outside the cage. But a fourth straight win for Aldo might be a better story. Aldo's constant reinvention after difficult defeats has been startling to behold, especially for someone as accomplished with so many miles on his fight odometer.  

5. Coming attractions at heavyweight: Meet Alexander Romanov  

A 31-year-old native of Moldova, the accomplished wrestler known simply as "King Kong" has been terrorizing the UFC's heavyweight division through five fights, albeit far under the radar of the typical discussions surrounding the division. But while the MMA world waits for Jon Jones' inevitable heavyweight debut, Romanov has quickly established himself as an interesting prospect moving forward. He has yet to go the distance in his pro career and is 16-0 overall. Romanov, who faces the battle tested Marcin Tybura this weekend, remains a 4-1 betting favorite to stay unbeaten and has both the size and physicality in terms of his grappling to be a legitimate problem for anyone should he stay on the winning path.