The game is Warhammer Quest: Silver Tower, the first Age of Sigmar board game, and likely to pull new people into the tabletop game.
via Lady Atia on War of Sigmar
Sorry Atia for my confusion on what was what.
via Sad Panda onDakka
The working title in the studio is or was Warhammer Quest: Silver Tower.
Will it be the final product name? I don't know.
The concept is a dungeon crawl in an ever-changing labyrinth of Tzeentch, slaying Horrors (that just turn into more, smaller Horrors) and other creatures of Tzeentch.