Activision Blizzard has won a nine-year lawsuit brought against it by Worlds Incorporated.
The self-described "leading intellectual property developer and licensee of patents related to 3D online virtual worlds" originally sued Activision Blizzard back in 2012 for allegedly infringing on five of their patents. These patents covered a "system and method for enabling users to interact in a virtual space," essentially claiming in their lawsuit that they had invented avatars, 3D multiplayer and the ability to interact with other players in a 3D space (thanks, PCGamesN).
Worlds Incorporated specifically cited World of Warcraft and Call of Duty as main culprits and requested Activision Blizzard cease the infringement—presumably by shutting down their games—and paying out for the supposed patent violations.
Activision Blizzard argued that you can't really patent something as vague as 3D multiplayers and systems for filtering players in a 3D environment, as well as retaliating with a small lawsuit of their own in 2013 (via GamesIndustry).
The Court eventually sided with Activision last month, saying that World Incorporated's patents were "abstract ideas" and the generic steps listed in their patents do not "provide the inventive concept to convert the abstract idea into a patent-eligible process."
While not exactly a lawsuit battle of Epic and Apple proportions, it's certainly a weight off of Activision Blizzard's shoulders—after all, it's not exactly the only lawsuit they've had to contend with recently. The company has recently been sued over Modern Warfare character Mara, as well as a lawsuit from a webgame called Warzone.