Fortnite

The monster that is Fortnite shows no signs of slowing down. It's got tens of millions of players and is one of the few games to be an honest to God cultural phenomenon as children, celebs and footballers alike floss like crazy whether they've played the game or not. What's even more amazing is that its 100 player battle royale mode wasn't even the main game. It started life as a co-op crafting and survival game that added on battle royale to catch a bandwagon and ended up taking over the world. While its building and battling gameplay are already strong, it is used of seasons - with constantly changing meta stories, secrets, mechanics, and items - which it stays fresh even when the core mechanics remain the same.