It’s a spoiler alert so please keep it moving if you haven’t seen Avengers: Infinity War yet. If we all remember correctly, Doctor Strange make use of the Time Stone early on. In the beginning of the movie, Strange vowed to protect the stone before Iron Man and Spider-Man’s very own lives for the universe’s sake. But his use of the Time Stone revealed to him over 14 million outcomes and the Avengers only won one of them.
When Thanos was about to finish off Tony Stark, Strange jumped in verbally and offered the Time Stone to Thanos in exchange for Stark’s life. Towards the end, as Strange is disintegrating, he looks to Stark and tells him “there was no other way,” indicating he did what he had to do in order to take down Thanos in the future.
Now the question is, why Tony Stark? Why Iron Man? We’ve always dubbed Stark as the “billionaire genius playboy philanthropist,” but he’s not just that, he’s a futurist as well. While the rest of the surviving Avengers will dwell on the past and what just happened to their fallen soldiers, Stark will be the one to snap them back to reality because he is always looking into the future to recognize what possible threats could come about and how to eliminate those threats while coming up with permanent solutions so it will no longer be a problem in the present or future.
There’s been quite a few clues that time travel will be the “thing” for Avengers 4, which makes perfect sense as there have been set pictures that indicated such and the ending of Infinity War could not possibly end in such a devastating way for good. Doctor Strange knows something we all don’t and that may be how Stark takes time-travel to another level and undo all the damage Thanos has caused.