As I understand it, licenses for the in-game characters have expired, and the game is no longer available in the Steam store. Sad - as this (and the original) are among my favorite poker games.
Poker Night at the Inventory was delisted from Steam on May 23rd, 2024. Although Telltale did not offer the same kind of explanation that they did regarding Poker Night 2, the game was likely delisted due to expired licensing of one or more of the properties featured in the game.