While Avengers: Endgame marked the sendoff for three major MCU characters—Tony Stark, Natasha Romanoff, and Steve Rogers—fans are understandably curious if “the end” really is the end. Scarlett Johansson’s Romanoff returns in her own Black Widow solo movie next year (although it’s a prequel that takes place before the recent Avengers sequels), and rumors are already swirling about where Robert Downey Jr.’s dearly departed Tony Stark might make a cameo. The one Endgame character whose ending wasn’t an explicit death was Steve Rogers, who went back in time to replace all the horcruxes Infinity …