The first DLC pack for CoD: Advanced Warfare will include the new zombie mode.
Three more DLC packs (Ascendance, Supremacy, and Reckoning) are due to be released at later dates, with Season Pass holders receiving them at a discount compared to buying them all individually.
Early access to the DLC1 bonus weapon - AE-4-Widowmaker directed energy assualt rifle - will be given to Xbox One players on 11th December 2014.
Over on Sledgehammer Games' blog the developers talked about the Exo Zombies mode a little, saying: "As things were wrapping up around launch, we started playing around with the idea of what happens when zombies were thrown into the mix with exoskeleton gameplay. What we came up with is Exo Zombies — an entirely new breed of zombies and an entirely new co-op experience that is truly unique to Advanced Warfare."
They also promise more info on the new mode "in the next few weeks."