USAgent

Listen, I'll do you one better: for the sequel, have BOTH Panther AND Cap fighting their way through trials to claim the respective mantle of Black Panther and.... Captain America. Have Steve, Sam Wilson, Bucky Barnes, and yes, Join F Walker on the Cap side, doing it big. Have the characters from your idea on the other timeline/"side" of the game going for BP, adding one more like MBaku or better yet, this new son of TChalla who just earned the throne in the comics. Yes, the white one. At the pinnacle, the winners begin to battle it out but wind up joining forces. Now THAT would be a daggone game!!!!

I think it will end similarly to the comics. It will be around the time of secret wars, maybe in Cap 5 after that, where he hands the mantle of to a new Cap, and goes back to being Falcon (alluded to in the end). For a minute in this film, he and the new Cap will fight side by side.