Turtle Rock Studios, the developer behind Left 4 Dead and Evolve, is working on a brand new IP. The news comes from a job listing on the company's website that asks for an animation programmer that will be working on "an unannounced, cutting edge game targeting next generation hardware." The position requirements demand years of experience, with preference for someone who is knowledgeable of AAA development software such as CryEngine or Unreal Engine 4.
The job responsibilities stated by the listing include extending engine and game animation systems to enable high quality features; working with animators to deliver "excellent combat, character locomotion and movement mechanics, and cinematics;" collaborating with various other team members to create solutions to challenging problems in "complex game worlds;" and "proactively identify and fix bugs and performance problems in core engine and game systems."
There's no way to speculate at this stage what the new game will entail, but Left 4 Dead and Evolve both focus on four-player cooperative gameplay against player controlled enemies. The latter launched in February of last year to mixed reception, but with terminology such as "complex game worlds," "cutting edge," and "targeting next generation hardware," it is certainly evident that Turtle Rock Studios has high hopes for this new IP.
Source: Turtle Rock Studios