Modern Warfare III and Call of Duty: Warzone will get cloud support for Game Pass Ultimate members. Microsoft points out in the blog post that it's "a first for the Call of Duty franchise ...
The $14.99 a month Xbox Game Pass Standard tier does not include day-one releases, and so won’t include Black Ops 6. Black Ops 6 is the first Call of Duty game to launch day-one on Game Pass.