"new zombies" refers to the idea of zombies taking on different characteristics or qualities that haven't been seen before. It suggests that the traditional concept of zombies is changing or evolving in some way. Full definition
It does seem to follow the former Call of Duty DLC route though, meaning 4 multiplayer maps, and one new zombie map. (playstationenthusiast.com)
Set to create a brand new zombie game, they are in need of an artistic individual to help shape the undead creations of the future. (letsmakegames.org)
But apart from a couple of new zombie types that's really it for brand new ideas. (metro.co.uk)