The Call of Duty franchise, and thus Activision are under fire lately by the corporation that creates the military vehicles fondly known as the Humvee. AM General LLC has apparently been in talks with Activision for over a year in an effort to settle their dispute, but no common ground has been met. It's because of this that AM General has gone ahead with an official lawsuit.
It was filed in Manhattan and has all kinds of interesting accusations. One claims that Call of Duty has been popular only because of the unofficial connection to AM General. The makers of the Humvee also claim that the vehicle is a major selling point in the franchise. All of this is contained under the umbrella accusation that Activision “took advantage” of AM General's “goodwill and reputation.”
AM General isn't wrong, the Humvee has been used in many Call of Duty games. The full list includes: Call of Duty: Modern Warfare Remastered, Call of Duty: Modern Warfare 2, Call of Duty: Modern Warfare 3, Call of Duty 4: Modern Warfare, Call of Duty: Modern Warfare: Mobilized, Call of Duty: Heroes, Call of Duty: Ghosts, and Call of Duty: Black Ops 2. Modern Warfare 2 even has a section where players are required to ride in a Humvee and man the gunner position.
AM General also refers to in-game dialogue where characters mention returning back to a Humvee. The vehicles also use AM General's trademarks including Humvee 01 M1026 HMMWV.
It's unclear at the moment how this court case will progress, but it's clear that AM General has done their research.