PUBG had its official release for PC in 2017, with console ports for PlayStation 4 and Xbox One following in 2018. A mobile version of PUBG also released in 2018. The game is technically named PlayerUnkown’s Battlegrounds, but just about everyone (including its developer) just calls it PUBG these days. Although Fortnite is the battle royale king, PUBG is still a giant hit that has sold over 50 million copies (and helped pave the way for Epic to add the battle royale mode to its game). These updates and new seasons are important for keeping its players engaged and spending money.
Season 4 notably brings some big visual updates to the game’s original map, Erangel. It also adds a new Survivor Pass (PUBG’s take on the battle pass) that unlocks cosmetic rewards for players who progress through it.
You can the patch notes for the update here.