Marvel Cinematic Universe fans are eagerly waiting to see Hulk on the big screen in Avengers: Endgame movie. There are several theories about Hulk and Thanos but as per recent speculation, Bruce Banner's alter ego, Hulk, will appear in Avengers: Endgame after the death of the Mad Titan.
In Avengers: Infinity War, Hulk did not come back after his initial defeat by Thanos on Thor and Loki's spaceship. Throughout the movie, Bruce Banner pleaded to him to come out and fight but he chose to deny all those requests. In the end, Banner had to fight wearing the Hulkbuster which Tony Stark has created.
Fans from around the world are eagerly waiting to see Hulk coming back to life and fighting everyone. Smashing anything that comes in front of him. But as per a fan, in Endgame movie, Hulk will only appear after the Avengers and Captain Marvel will put an end to Thanos.
As we all know, Thanos will die in the first 20 minutes of Avengers: Endgame. So, in the first 20 minutes, we will see how Bruce Banner will continue his struggle to summon his superhero alter ego. But after the defeat of Thanos, Hulk will feel comfortable again and will come out for the very first time.
Hulk's appearance after Thanos' death would not be of much help to Avengers but if they all use Ant-Man's Quantum Realm to go back in time and reverse everything, then Hulk would prove to be the most helpful one. This time, after the reversal, he will know that in the end, they will win the war and he won't be "smashed" again by Thanos.
In the very first trailer of Avengers: Infinity War, we saw Hulk alongside Steve Rogers in Wakanda, fighting Thanos' army. So, if this theory holds any truth, then after killing Thanos, Hulk will come back and join Steve Rogers and the rest of the Avengers in their fight against Thanos' army.
That being said, a fight between Hulk and Thanos would be extraordinary and even the makers know this that fans are eagerly waiting to see Hulk on the big screen — that is why he is missing from all the marketing clips of Endgame movie. The fourth Avengers movie is slated to release in April.