Avengers: Endgame ended with Captain America aka Steve Rogers using time travel to return the Infinity Stones. This was to keep Bruce Banner’s promise to the Ancient One from Infinity War.
Missing Stones in different dimensions would the other timelines/reality be prone to attacks. It would cause a branch in the Marvel Cinematic Universe. Since this is the era prior to WandaVision and Doctor Strange and the Multiverse of Madness, Cap had to be careful to keep things in their natural order.
We’ve been told different takes on Caps’ journey at the end of Endgame from the directors, Joe and Anthony Russo, and the writers. With Falcon and the Winter Soldier coming soon, it is more important than ever to understand Cap’s journey.
Endgame ended with Cap returning to our initial timeline to hand off his shield to Falcon (Sam Wilson). These events will basically be the inciting incident in the new Disney+ show.
Talking to Light Camera Barstool podcast, Joe Russo gives us a more definitive answer about Endgame‘s ending involving Cap:
One thing that’s clear that Anthony and I have discussed, I don’t know that we’ve discussed this publicly at all, Cap would have had to have traveled back to the main timeline. That’s something that, yes, he would have been in a branch reality, but he would have to travel back to the main timeline to give that shield to Sam Wilson.
In our internal logic that we defined in the room, that was the choice that we made. Based on everything that happened, he would have been in a branch reality and then had to have shifted over to this, so jumped from one to the other and handed the shield off.
This makes perfect sense. In order to hand off the Shield to the next Cap, he’d have to return to his “home” timeline at some point. Otherwise, we wouldn’t have a show… or the show would be stuck in a different timeline/reality.
Now that this issue is again cleared up… GIVE ME Falcon and the Winter Solider!