They know it will sell well call of duty has a pretty loyal fan base personally I don't like it though.

High ROI.

I’ve never played COD, but I do know it’s history. What annoys me though is the fact that I’m watching YouTube I get an add and I’m interested wanna see what it is and It turns out it was the new cod game. I’ve never been quite so upset at a video game add in my life. Anyway I’m not interested in it. As for your question; money. That’s one of the biggest brands in the gaming industry so they have to make a new game. It’s brand recognition, people will buy it; just because it has the name.

Like any Call of Duty, just slap a new number and try to extend the story of previous much better games. I guess when one can't have creativity to make an original idea settling for nostalgia is the only option. Modern Trendfare may I say?

Pretty sure it has something to do with greed