World War Hulk is a revenge event centering on the green monster’s fury at the heroes of Earth (specifically The Illuminati) for shooting him into space and (in his mind) killing his pregnant wife on Sakaar when the spaceship they used to send him away from Earth explodes.
It’s a world-spanning showdown in which Hulk fights all of his former allies, but it wouldn’t make sense for the current arc of Mark Ruffalo’s Hulk in the MCU.
A lot would need to happen in the MCU for World War Hulk to occur, and given the fact that Planet Hulk is already receiving a loose adaptation during the events of Thor: Ragnarok, the odds of it happening seem unlikely.