Speaking of Bethesda, another one of its iconic franchises is Fallout. In Fallout 4, explore Boston, Massachusetts in a post-apocalyptic setting called "The Commonwealth", set 10 years after the events of Fallout 3.
You play as the "Sole Survivor" who has been frozen and asleep in Vault 111. You search for missing son after seeing your spouse killed, and The Commonwealth has many places for you to explore and quests to take on. You can manage settlements and craft items to help you along your journey.
Fallout 4 was available on Game Pass in the past, but has since left the subscription service. Hopefully, along with 2016's DOOM, Fallout 4 could also be added back sometime in the future. Fallout 3 is backwards compatible with modern Xbox consoles, so that's a great title to play as well.