Call of Duty: Black Ops 7 campaign's Endgame mode is going free to play for a limited time with the April launch of Season 3 — plus new content and changes to Combat Rating are on the way

Treyarch aims to release Black Ops 7 campaign's Endgame mode for free as part of Call of Duty: Warzone with the Season 3 update on April 2. Free-to-play access to Endgame is only for a limited time.

source https://www.windowscentral.com/gaming/call-of-duty/black-ops-7-season-3-endgame-free-to-play