It was like that in the beginning. I'm not a gamer, but that series has a lot of cool subtitles. Like 'Call of Duty: Modern Warfare III' or this year's 'Call of Duty: Black Ops 7.' Modern Warfare takes place in the present day, while Black Ops takes place in the future, offering a pure science fiction story. So, the first Call of Duty games were World War II-themed games that could be simple and cheap to adapt. The current ones aren't like that. If they're going to adapt the first games, it's easy. They'll do it cheaply. If they're going to adapt the Modern Warfare and Black Ops series, they'll have to shell out a lot of money. They've also started casting some pretty big names in the latest games. In this year's Black Ops 7, they're bringing in some more "well-known" TV actors who have also appeared in movies, like Milo Ventimiglia, Kiernan Shipka, and Michael Rooker. Years ago, they cast Kit Harington in a game.
Of course, I have to say that every COD game is a military shooter game, but they haven't made a World War I or World War II game since 2007.