This comes as a surprise to all of us. Kotaku has reported WoW related matters available in the latest Wolverine game.
A picture of a hidden area in the game (which is apparently at the Akali Lake Weapon X facility) shows the most recognising artifact – related to Warcraft.
The achievement has a nice name too:
"WoW!" with the description, "You feel cold as you examine the skeleton and read the name "Arthas" etched into the nearby sword."
The picture:

This is just one of perhaps many others.
Still waiting for more discovery.
[via Kotaku]