As you surely know by now, games are constantly being added to Xbox Game Pass - but occasionally they are also removed as MS looks to keep the line-up feeling fresh. The latter is often true for bigger third party titles, and now a new bunch of games are confirmed to leave the console service at the end of February.
Those are Batman: Arkham Asylum, Batman: Arkham City, Just Cause 4 and Rise of the Tomb Raider. Snake Pass will also be removed, and this applies to the PC version of Game Pass as well. If you still haven't played those but intend to, now is a good time to do so.