The last we saw Iron Man, he was stuck on Thanos’s home planet Titan. With seemingly no way out from there. However, we see Iron Man back on Earth with his fellow Avengers in the trailer the creators dropped a month ago. So, even though we know that Tony Stark will return to earth, and possibly within the first 20 minutes of the movie, we don’t know how that will happen. Of course, as a part of the fandom, every one of us has our own theories.
Here’s something that was strongly hinted in the Endgame trailer: Nebula is on Titan too. Since she is almost practically a robot, she probably was not affected by Thanos snapping his fingers. Or, maybe, she was one of the lucky few ones to survive the snap. Either way, having her on the planet with Tony can be very valuable as unlike Iron Man, she is well versed with alien technology, particularly space crafts. Speaking of which, we also know that the Benarar, which is a ship that belonged to the Guardians of the Galaxy, is up there. We’ve seen Iron Man inside a spaceship, recording messages to Pepper Potts, so we know that he definitely finds a ship that will take him home somehow.
Perhaps he may team up with the remaining Guardians at some point to get to Earth, or he may be rescued by Thor, who has also travelled with the Guardians and developed a good friendship with Rocket. The intricacies of how he will return are a bit unclear but we do believe that both, Nebula, and Benarar are both going to play a vital role in helping Tony Stark get home.
The more interesting question is, will he still have the willpower to continue fighting after what happened to Spider Man or will that only fuel his vengeance further? Remember, he does not know who is dead and alive on Earth and is definitely in for a shocker once he reaches his home planet.