One of the biggest questions about Avengers: Endgame was how Steve Rogers would return the Soul Stone on Vormir, especially counting that his old nemesis the Red Skull basically lives on that planet. With all the fan speculations and theories going around the Russo Brothers have given the fans a definitive answer.
When asked during their Reddit AMA what Steve's reaction would have been to see the Red Skull, they said Cap wouldn't even recognize him. Anthony Russo replies: It was probably more awkward than you imagine it was. Red Skull felt slated because Cap didn't recognize him.
This was probably a joke on Russo's part, but I can imagine a lot of fans taking it seriously. If anything, returning the stone would make Natasha's sacrifice null, and I don't think there's a way she could be "traded back" for it. At best, I think Steve would just leave the Soul Stone with that timeline's Avengers or SHIELD. Maybe he can even hand it to the Widow from that time and tell her what it took to get it.
For now, it looks like Steve Rogers' journey is officially done, and fans are waiting to see how Sam Wilson becomes the new Captain America in Disney+'s The Falcon and The Winter Soldier. We don't have a specific release date for the series yet, but it's expected to come to Disney+ sometime around the fall of 2020.
Black Widow comes out on May 1, 2020.
See Also: Avengers: Endgame Directors Now 'Quietly And Secretly' Working On New Franchise