https://www.techdirt.com/articles/20180529/09432639936/pubg-corp-sues-epic-games-s-korea-over-gameplay-similarities-that-probably-arent-copyrightable.shtml

The last time we checked in with PUBG Corp., the company behind the popular PlayerUnknown's Battlegrounds video game, creator Brendan Greene was remarking on how video games are afforded no intellectual property rights at all, despite that absolutely not being the case. This confused take on a key aspect of his industry came on the heels of the developer of PUBG suggesting that it was considering suing Epic Games, the makers of Fortnite, for copyright infringement because Epic had updated its own game with a "battle royale" mode. Like PUBG, this mode pits 100 people against each other in a last-man-standing battle format. It was at that time that we tried to remind PUBG Corp. that the idea/expression dichotomy in copyright law is a thing. While specific expression gets copyright, general concepts, such as generic game-modes and genres, do not. A battle royale game format is no more deserving of copyright than the first-person shooter genre.

It seems that the lesson didn't take, however, as it was recently revealed that PUBG went ahead and filed a lawsuit in South Korea way back in January.