Avengers: Endgame movie trailer gave us the glimpse of Avengers trying to move on in their lives but at the same time, it showed Steve Rogers aka Captain America (Chris Evans) planning something very desperate. There are several theories about Captain's plans but what makes Endgame movie interesting is the probability of seeing time travel in an MCU movie and it will probably be done by Doctor Steven Strange (Benedict Cumberbatch).
In Avengers: Infinity War, fans were left heartbroken after seeing the damage done by Thanos' "snap." In the final scenes of the movie, we lost several of our favourite superheroes including T'Challa aka Black Panther (Chadwick Boseman), Peter Parker aka Spider-Man (Tom Holland), Dr. Strange and others. As per the latest fan theory, Dr. Strange sacrificed himself because of Tony Stark aka Iron Man (Robert Downey Jr.).
As per a Redditor, "Strange foresaw that the assembled might of the Avengers would be enough to wrest the Gauntlet from Thanos before he was able to do so, though it is also possible that reversing the damage to the Gauntlet would also reverse what caused the damage, again thwarting Thanos' plans."
Apparently, this is not the first time when theories about Dr. Strange's time travel has surfaced online. Ever since the fans of MCU witnessed the horrifying climax scenes of Avengers: Infinity War, there have been talks on several forums about possible time travel. Even Samuel L. Jackson, who plays Nick Furry in MCU movies, has recently talked about Captain Marvel's ability to time travel.
It was previously speculated that when Strange gave away his highly valued Time Stone, he gave it to Thanos at a very specific moment. Maybe in his 14 million possibilities, he witnessed something about that specific time and picked it. There is another theory that connects Scott Lang aka Ant-Man (Paul Rudd) with Dr. Strange. Fans have conjectured that the time when Ant-Man enters the quantum realm in Ant-Man and the Wasp, is the exact moment when Dr. Strange gave time stone to Thanos, in a hope that Ant-Man will survive the "snap" and join the rest of the Avengers.
Check out the entire theory here: