The first in-season events have landed in Call of Duty: Black Ops 6, and one, Echoes of the Dead, is exclusive to multiplayer. The rewards can be used across other modes, but to get them at all, you have to jump into multiplayer and complete the requirements.
Fortunately, even if you're not a regular in the mode, it's a really simple event to complete. The challenges can be done simultaneously, so it's possible to chalk off multiple in a single match.
