Anthony Mackie and Chris Evans spent five years making Marvel movies together as Sam Wilson/Falcon and Steve Rogers/Captain America. Their characters were close friends, with Steve bestowing the Captain America shield to Sam at the end of 2019’s “Avengers: Endgame.

But exactly what the plot of that movie actually is is anybody's guess. We know that it will include the return of Robert Downey Jr., now playing Doctor Doom, but an intriguing theory suggests how a potentially returning Chris Evans and Captain America may factor in, and how it will actually all tie into Avengers: Endgame.