Its an all zombie dlc coming up for the forth Black Ops DLC. The rezurrection pack contains:
A new ‘Moon’ level, featuring new weapons (Wave Gun & Quantum Entanglement Device), plus a new perk.
Four re-mastered levels: Nacht der Untoten, Verruckt, Shi No Numa and Der Riese, the Zombie factory. That was included in the Hardened and Prestige Editions (This DLC is free for those that have that version).
Announcement over at Call of Duty