Several sites have noticed there is a console (PS4) game with a working title of Project Mephisto that has been nominated for an award (best console game) at Gamescom 2018 alongside Assassin’s Creed Odyssey and Marvel’s Spider Man. Variety was one of the first sites to report this without a lot of the Blizzard universe going into a hype frenzy.
Given the recent announcement by Blizzard that they would be teasing some of the multiple Diablo projects later this year, there is speculation this could be a possible working codename for Diablo 4 (which given the success Diablo III has had on console, is more than likely being developed in tandem with the PC version).
Blizzard has already officially announced the Nintendo Switch version of Diablo III. There was also a teaser that someone found in a (now deleted) tweet made on August 18th at 7PM (European time) by Blizzard Germany for a Heroes of the Storm image for possibly the next hero in the game (i.e. Mephisto).
Gamescom 2018 of course takes place in Cologne, Germany on August 21-25 and Blizzard will be there. However, when they officially announced Reaper of Souls back at Gamescom 2013, they did that very elaborate build up starting with a cryptic image on their site and then on their Chinese partner (NetEase) site with a series of teaser reveal images (and I also included in that article about the teaser image reveal they did for Diablo III preceding the official announcement at the 2008 Blizzard Worldwide Invitational in France).
The above seems way too little for a D4 announcement at Gamescom though. There is also speculation this could be a port of Heroes of the Storm to the PS4 (which I doubt given how Heroes of the Storm isn’t exactly this blockbuster hit on the PC).
It’s very possible that this Project Mephisto has absolutely nothing to do with Blizzard and Diablo 4 and could be a codename for a Sony related project from their Xdev team which is based in Europe (and would make the most sense since the nomination is for a PS4 console title and it isn’t Blizzard like where they will exclusively release it for just one console platform). I guess we’ll find out in a few days whether or not this actually has something to do with Diablo 4 and if its theme will involve Mephisto.
UPDATE: There is speculation this could be Supermassive Games new game which they recently filed a trademark for in Europe (Shattered State). This sounds a lot more plausible given their prior PS4 titles.
Gamescom UPDATE: Blizzard confirmed Mephisto is the new hero for Heroes of the Storm.

