https://www.pcgamer.com/call-of-duty-black-ops-4-may-have-a-battle-royale-mode-instead-of-a-campaign/

Call of Duty: Black Ops 4 was confirmed in early March, but isn't slated to be fully revealed until May. Today, however, Polygon dropped a big rumor bomb by citing multiple sources who say that the game will ship with no single-player campaign at all, on any platform. 

The sources claimed that the campaign was cut because there just wasn't enough going to be enough time to get it done prior to the October 12 release date. Instead, Treyarch is apparently focusing on expanding the multiplayer element, including the Zombies mode and possibly some new co-op modes.