They didn’t omit Zombies but that mode is only ever in Black Ops games.
That’s not true. This is the first CoD without Zombies since Ghosts, and even that had the weird Alien Mode so you could argue that it’s been since Modern Warfare 3 in 2011. Infinite Ward’s last game, Infinite Warfare, was a really good Zombies mode to boot.
I’m not saying they should have included it. It doesn’t fit the theme of the rest of the game at all.