Post Update: Added proper credit for ImChuckyFTW.
The fact that Black Ops 2 is set to receive another DLC is no secret. However, fans prying into the source code of the game's official website have uncovered what appears to be a reference to the name of that DLC—Uprising.
A line within the source code of the official website's Revolution page reads as follows:
background: #000 url(‘/content/dam/atvi/callofduty/blackops2/cod-bo2/dlc/dlc2-uprising-bg.jpg’) center top no-repeat;
The proof is in the pudding.
The line was discovered by community member MrDalekJD.
Another community member, ImChuckyFTW, found a product teaser for an Xbox Live themed for Uprising, which reads as follows:
"Download the epic Call of Duty: Black Ops II Uprising Theme, featuring Studio, Vertigo and the Mob of the Dead, Treyarch's most terrifying Zombies experience to date."
What's interesting to note is that Vertigo was a cut map from Modern Warfare 2, suggesting that it may be making a proper appearance in the upcoming DLC—assuming that it's real, and that the developers at Treyarch or whoever's handling the map pack decided to salvage the original Vertigo instead of simply naming a new map with the same name.
The reference to Mob of The Dead may also be a sequel to the first Black Ops' Call of the Dead zombie mission—but that too remains to be seen.