Several years ago I read an article which put forth the notion that zombie media tends to do better when Republicans are in office, while vampires fare better when Democrats control the White House. That's the only reason I can think of why anyone would choose 2019 to release a game based on the six-year-old World War Z movie, itself based loosely on the 13-year-old novel of the same name.
If you've heard about World War Zat all, you've probably noticed some of the distinct similarities to Valve's Left 4 Deadfranchise. World War Z is at the very least an homage to Valve's zombie shooter, though there are enough differences that it doesn't feel identical when you're playing. It's true WWZ is derivative, but it's always been the case that if you're going to steal, steal from the best. Besides, it's been nearly ten years since Valve has done anything with the idea, so why not let someone else take a crack at it?