Theres actually a quite complex story behind it, and i am sorry that i can not list all the details but look up:
Cod 5 WAW Zombies Storyline. It explains how a crazy scientist made the zombies and the hellhounds.
Bill Gates !
It was made by computers of course!
Black Ops does have zombies
Yes there will be zombies and zombies campain
Yes, CoD Black Ops 2 has zombies.
cod: world at war & cod: black ops
yes
the new black ops has
Black Ops has a zombie mode
no
In zombies yes but online no
you mod
There is definitely zombies in COD BO, even though it was made by different people to WaW.
You don't get that