Blackout. Black Ops 4 features a battle royale game mode called Blackout which serves as a stand-in for the campaign mode. While utilizing the traditional Black Ops combat style, the mode includes the largest map featured in a Call of Duty title.
Just be warned you can't play Blackout while offline. The other modes are locked because they haven't finished downloading. When you play offline, the only 2 modes you can play are Multiplayer and Zombies. So when you log on you'll see the 3 modes.