This is the new game type Pokerstars has in the works. From what we can tell, it seems to combine elements of modern card games (like Hearthstone and Magic) with poker.
Personally, I'm excited for new games like this. I think there's a gap in the market for new real money competitive games, and that Pokerstars is in the right position to start capitalizing on this gap. Moving forward as traditional poker variants become more and more solved and infested with centaurs/bots, these games have the potential to revitalize the dream and attract more fish.
On a more general note, Pokerstars seems to be off to a good start in 2017. With the recent proactive bans (locks/investigations?) of Oborra and 40and7, and now this, they appear to be focused on the future in a way that is finally more mutually beneficial to the players and their company.