While Bruce Banner was present throughout all of Avengers: Infinity War, Hulk only showed up at the beginning to fight Thanos, though he was swiftly defeated.
Although the fact that Hulk’s face looks more human suggests that fan theories speculating that Hulk and Banner will somehow merge together might be correct.
Infinity War co-director Joe Russo explained that the reason for Hulk staying buried within is because he’s “had enough of saving Banner’s ass,” but evidently their issues will be resolved if Hulk is willing to come out for Avengers: Endgame.
That would certainly make for an interesting conclusion to the Hulk arc that began in Thor: Ragnarok.