https://thenextweb.com/gaming/2019/10/21/diablo-4-leak-blizzcon-reveal/

We may be seeing the resurrection of an iconic franchise soon. A leak in German magazine Game Star may have just spilled the existence of Diablo IV, the latest entry in the dungeon crawler series.

The telltale reveal was in an ad for a Diablo art book. It claims the book (which you can pre-order on Amazon) contains “over 500 artworks from Diablo, Diablo II, Diablo III and Diablo IV.”