Turtle Rock Studios, the developer of the Left 4 Dead franchise, have officially been deemed guilty of working on a yet to be announced AAA game, with job listings on their site mentioning an FPS title in a "globally known franchise".
As is common with these things, the news came the way of eagle eyed users, who've pieced together bits and pieces from Turtle Rock's job ads. Still, it's more than plenty to get an L4D fan going, with the question of Left 4 Dead 3 lingering on their lips for more than just a while.
One of the listings is looking for an experienced environment artist, where "experience with AAA First Person action titles is a big plus." Another ad is looking for someone with experience in working on competitive FPS games and with experience in modern FPS engines, with the name Unreal Engine 4 commonly flung around for good measure.
With responsibilities listing designing of "competitive and balanced map layouts", it's safe to say we'll be seeing an FPS, so now it's just a matter of which one. Be warned, we're entering the Speculight Zone now.
Rumourville seems to agree on two possibilities - Red Rock is either working on Left 4 Dead 3 or Evolve 2, even though the latter isn't quite what you'd call a "globally-known" franchise.
You may recall Evolve as Red Rock's first post-Valve game but the game's critical response and populations didn't really correlate. It's free to play on Steam, by the way, so you can go and see for yourself. This would leave only Left 4 Dead 3 as the possible outcome, which would elevate it slightly above wishful thinking.
Back in 2016, Red Rock stated they were working with Perfect World Entertainment, a free-to-play publisher, on a new franchise set in a "new universe", which would obviously disqualify it from this round of rumours. However, with the company being pretty quiet for a while now, it may be that their project has gone through some radical shifts in the meantime.
Turtle Rock Studios
Red Rock haven't had anything to say on the subject. Yet.