Ubisoft has filed a lawsuit against both Apple and Google over allegations that a game named Area F2, available in the app stores of both companies, is a "carbon copy" of Rainbow Six Siege.
According to the lawsuit, as reported by Bloomberg, the game is a "near carbon copy" in "virtually every aspect" and alleges that both Apple and Google have failed to remove the game from their app stores following DMCA takedown requests.
The game, made by Ejoy, is described as a "Close-Quarters Battle (AKA CQB) shooting game on mobile," and was released last month. It is, admittedly, strikingly similar to Rainbow Six Seige, although it wouldn't be the first mobile game to walk that fine line.
As such, it's hard to say how the suit will pan out. The game does not use any of Ubisoft's assets as far as I can tell but is strikingly similar in concept. Copyright law is complicated when it comes to video games, and clones of video games have existed since the days of Pacman.
Game mechanics cannot be claimed as copyright law, at least in the United States, so it falls to the visual design elements for the suit to be successful. It also remains to be seen how liable Apple and Google are in this case, although I imagine the game may find itself delisted should the companies decide they don't want to go through litigation.