The next major addition of the GWent KKI will be released on June 30, and one of the most mysterious villains of the Witcher 3. Gunter O'Dim will play the main role in the addition of Mr. Mirror.
The addition includes more 70 new cards, some of which are exclusive for certain fractions. New developing cards will be entered into the game, and they will become more and more with each round. It seems that there will be six such cards, the first set of which will be disclosed on June 6th.