The Witcher: Legends.
As was rumored, so it shall happen- this seems to be the theme of the Microsoft E3 press conference so far, all of which, it appears, was leaked beforehand at this point. One of those leaks was for Gwent, a standalone version of the excellent collectible card game minigame from The Witcher 3. It looks like it is being developed into a full fledged game now.
CD Projekt RED spent quite a time showing the game off, discussing how they received so many requests for it, and how the game will have its own epic single player campaign mode. In a lot of ways, it sounds like Gwent will be CD Projekt RED’s counter to Bethesda’s The Elder Scrolls Legends. CD Projekt RED also promised that Gwent would be as much about the player’s skill, as it would be about the cards themselves.
Gwent will be launching in closed beta on Xbox One and PC in September. Presumably, it launches for other platforms later.