Gwent was so popular in The Witcher 3 that a stand-alone version called Gwent: The Witcher Card Game is being developed and is in beta right now. The designer responsible, Damien Monnier, has recently been hired by Techland, the Polish developers of Dying Light. He's been hired as their lead designer for a new fantasy IP.
Techland is developing two new titles, one of which is the new IP they've hired Monnier for. It's to be an open-world fantasy game with RPG elements. They have said that these elements "maybe in a slightly bigger sense than Dying Light … [but] it's RPG elements rather than RPG game." It will also have co-op multiplayer and single-player elements.
Being with The Witcher from 2012-2016, moving Monnier to an open-world fantasy game seems to be an easy transition, especially when the team he was moved to is in Warsaw, same as CD Projekt Red. Monnier was a senior gameplay designer for The Witcher 3: Wild Hunt and the lead designer for Gwent: The Witcher Card Game.
Techland told Eurogamer: "As a whole, we're extremely excited to welcome all the recent additions to the Techland family. We've got really big ambitions for our next internally developed games so people with ingenious ideas as well as the skill and knowledge to bring them to life are absolutely essential."
While the decision to leave CD Projekt Red is unclear, Monnier described it as a mutual and friendly decision and publically thanked the studio after the change.