Following on from the Modern Warfare 2 campaign missions, Spec Ops missions see familiar characters returning to the fray, and each of the maps are based in or around Al Mazrah, just like Warzone
Ultimately, Modern Warfare 2 has extremely promising multiplayer and co-op gameplay that feels good to play on the surface but woefully underbaked due to a lack of features and overall content in
If you want the perfect co-op campaign games, I'd highly recommend The Master Chief Collection (MCC). It comes with 6 different Halo games within a rich sci-fi universe for only $40 (on PC, it might be full priced on Xbox). If you're looking for Call of Duty, World at War and Black Ops 3 are really the only COD games that support co-op campaigns.