Call of Duty: Black Ops II - Zombies had Steam trading card support added on 6 September 2013. There are 10 cards in the series, and you'll receive 5 cards at random for purchasing and playing the game.
The other variant of the game, Call of Duty: Black Ops II - Multiplayer, also has trading card support. Both sets come from the same game, but they are both series 1.