In Star Wars, Sabacc is a card game similar to Blackjack or Poker. However, in 2015 some guy decided to use the name for his own card game after finding it wasn’t trademarked, and when Lucasfilm found out they weren’t happy. It’s a famous game in the fiction so of course they’re going to use it in a story with both Han Solo and Lando Calrissian in it. But now the guy who created a real unrelated card game of the same name (although others have actually made a Star Wars Sabacc game, including a recognized “official” version) is suing over the use of the fictional card game in Solo: A Star Wars Story. This is like me suing CBS or Paramount if anybody referenced Fizzbin, the card game Kirk made up to fool some bad guys, that I homage with my alien character in Jake & Leon. I don’t know where Ren Ventures got the name from but are you really that surprised they want to use a name they (or possibly the novels–the wiki entry (bonus link) isn’t clear) created? I wouldn’t be surprised to learn he’s using the opportunity to get his game promoted with this. I know it’s the first time I’ve heard of his game and I couldn’t tell you if it matched the Star Wars rules or not.