A branded slot is a game built under licence from an existing brand: a film, TV show, band, comic or game show. The studio pays to use the name, characters, music or footage.
Branded games are found on fruit machines and online. The licence affects the look and the features, which often borrow moments from the source, but not how fairness works: the maths, RTP and rules are certified like any other game.
RTP still varies by game and version, as with any slot, so check the paytable for the figure on the version you are playing. Brand familiarity is a marketing tool, so judge the game on its rules, not the name.