User blog comment:Argorrath/Treyarch posts a message of zombies; possibly hinting to a DLC 4/@comment-67.176.72.34-20130731073357/@comment-67.176.72.34-20130731170816

Yeah I'm not thinking it will be all zombies. But, the last DLC for black ops 1 was all zombies, so who knows. Anything is possible.