Concept art for The Avengers 4 recently leaked online offering a look at the surviving Marvel heroes, following Thanos killing half the universe, where it shows off the Hulk in a new costume.
Now following the Marvel Studios presentation at CineEurope, it's again being claimed that the Hulk will get a new costume as attendees are said to have been shown new art where Hulk is described as wearing some sort of armor.
This is the previously leaked art with Hulk in a new costume:
It's unknown why exactly the Hulk might be wearing a new costume or armor for The Avengers 4, but there is a lot of speculation, which may tread into spoiler territory.
It's theorized and rumored that the Avengers travel back in time or go to another universe, which is a reason why the Hulk might need some sort of new suit or armor to protect himself from the effects of traveling through time or the multiverse (or even the Quantum Realm).
Another possibility, which harkens back to the Planet Hulk comics, is that the Hulk needs armor because he is weaker and not as strong as his regular self. It's theorized that Banner and Hulk merge for Avengers 4, which may mean a weaker version, but a smarter version.
The Russo brothers previously revealed the reason why the Hulk wouldn't come out in Infinity War is because he wanted to teach Banner a lesson. Now that the lesson has been taught, maybe the Hulk literally teams with Banner to save the fallen Marvel heroes.
Taking a closer look at the above concept art, the Hulk costume seems to resemble something that might come out of Wakanada, meaning that Black Panther's sister, Shuri, might make Banner a new costume to protect him.
Bear in mind as it is simply concept art, the final version could look a lot different once the movie gets released.
The Avengers 4 has a May 3, 2019 release.