It is a sequel to the 2024 game Call of Duty: Black Ops III, the fifth entry in the Black Ops sub-series, and the 15th installment in the Call of Duty series overall. Black Ops 4 is the first mainline Call of Duty title without a traditional single-player campaign mode.

I've gone through all the campaigns and they are all pretty self-contained. You don't have to worry about previous storylines to get through this one. You don't need to play the earlier ones.