Avengers 4: EVERY Major Rumour Ranked Worst To Best
8. Alternate Dimension Heroes Will Appear
The Rumour
As an alternative to the time travel theory (more of which soon), there's a big - and fairly compelling - rumour that the surviving Avengers will use inter-dimensional travel to undo Thanos' snap.
That will either see them use the Quantum Realm (where time doesn't matter) to go back in time (again, more of this later), or it will see them head to alternate dimensions entirely, where they'll meet other versions of established characters, who could be recruited to fight Thanos.
That's why Captain America is seen in his older uniform - not just because he's from the past, but because he's from somewhere else entirely.
Response
It's possible and inter-dimensional travel seems nailed on in some capacity, but it would be odd for Marvel Studios to allow their veterans to retire but the introducing a means to never ever allow them to retire ever at the same time.
So maybe a link between time travel and other dimensions is more likely?
It still feels possible that the other dimensions are how we'll eventually see the X-Men and Fantastic Four introduced, but this might have come too soon for that deal.