Normally it's the big publisher sending out cease-and-desist letters to the developer of a smaller games. This time it's the other way round. According to a complaint filed by Activision in the United States District Court for the Central District of California, the creator of a browser game called Warzone—who goes by the name Fizzer—sent Activision a cease-and-desist in 2020 and has opposed its application for a trademark.
Activision's complaint says it applied to trademark Warzone and Call of Duty: Warzone in connection with downloadable videogames and entertainment services in June of last year, while the defendant only filed for a similar trademark on Warzone four months later in October, and subsequently claimed that Activision's trademark "has already and will continue to result in the relevant consuming public being confused, mistaken or deceived" about the distinction between the two games.
As for the browser game in question, Activision sums it up with as much savageness as is possible in a legal document, saying that, "Call of Duty: Warzone could not be more different from Defendant's game, a low-budget, niche virtual board game like Hasbro's Risk" and "it is inconceivable that any member of the public could confuse the two products or believe that they are affiliated with or related to each other."
In November, the creator of Warzone the webgame (and its spin-off Warzone Idle, both now available on mobile) sent the cease-and-desist to Activision, saying that Warzone.com, LLC, "would be within its rights to seek to enjoin Activision from using the WARZONE mark and to recover monetary relief as a result of Activision's infringing use". That really seems to have upset Activision's apple cart.
Which brings us the complaint Activision filed this month, saying "Activision is entitled to a declaration that it has not infringed Defendant's alleged trademark and is entitled to have its pending trademark applications mature to registration." The complaint also notes in passing that "Defendant claims that it released Warzone to the public in November 2017," by the way, over two years before the release of Call of Duty: Warzone.