Gwent is a standalone card game included inside the Witcher 3: The Wild Hunt videogame by CD Projekt Red. It is available as a physical copy with the Xbox One Collector's Edition of the video game (Northern Realms and Nilfgaardian Empire factions) and in "Hearts of Stone"physical expansion for PC/PS4 (Scoia'Tel and Monsters factions).
Gwent has two players simulating a war between two of four factions: Northern Realms, Scoia'Tael, Monsters, or Nilfgaardian Empire. Players take turns adding strength to the battlefield until both players pass. The highest strength on the battlefield wins the round and matches are played best of three, with little to no card drawing in between rounds. Special cards may also be played to reduce the effect of certain unit types. Gwent also features various once-per-game leader abilities and deck building rules.