A piece of Avengers 4 promo art featuring the movie's roster of heroes has been doing the rounds online, and it appears to be genuine since reports coming out of the CineEurope 2018 in Barcelona suggest Marvel Studios used the same imagery there.
So assuming this team shot is the real deal, what can be gleaned from it? Well, the biggest reveal is that the Hulk appears to be sporting a new look. He's slimmer, wearing skintight armour and his features are more Mark Ruffalo-like.
This lines up with fan theories about the big guy becoming 'Professor Hulk' in Avengers 4. This version of the character is a halfway point between Bruce Banner and the Hulk, with the brains and wits of the former, and the strength of the later. It's basically what happens when the two passengers on board the same vessel unite.
It would make sense if this was Banner and Hulk's endgame. Bruce has had a hard time accepting the Hulk as a part of him in the past, and when we last saw Hulk in Infinity War, he was done playing the hero to the good doctor. Avengers 4 could see them both slay personal demons and pool their resources for the greater good.