Diablo community manager Brandy Camel has confirmed that Blizzard is working on more than one project in that game's universe. 

Through a video titled “The Future of Diablo” (below), Camel stated that Blizzard has “multiple Diablo projects” in the works. Diablo 3 will naturally continue to receive seasonal updates, but fans can likely expect more than just this continued support.

Following a successful remaster of 1998’s Starcraft, this could mean a substantial re-release of the earlier Diablo games. It may mean another major expansion for Diablo 3. Hell, there’s a chance this could be the first we hear of a potential Diablo 4.

As recently as this June, the Irvine studio was hiring a dungeon artist to work closely with level design - suggesting all-new content rather than a port or remaster. At the time, Blizzard dismissed suggestions that the series was preparing to make the jump to Nintendo Switch.