Turtle Rock Studio's messed up royally with their last game Evolve, so for any future projects they need to make sure their game works and is fun for extended periods of time. Good news is they may have an opportunity as they are reportedly working on a brand new game.
This news has been revealed thanks to a job listing on the companies website looking for an animation programmer. The position itself is listed for an "unannounced new" intellectual property described as a "cutting edge game targeting next generation hardware."
What Turtle Rock Studio's could be working on is anyone's guess knowing the huge difference between there previous intellectual properties Left 4 Dead and Evolve, in fact this property could be unlike anything we have seen before. However, a further look at the listing notes that among the responsibilities for the job listing is to "deliver excellent combat, character locomotion and movement mechanics, and cinematics" to the unnamed new game.
So if you were hoping the studio would be doing a sequel to Evolve next then you are sadly going to be let down. However you can expect a new Evolve one day given Take-Two's stance on the franchise, they declared last year that Evolve will be one of their "permanent" intellectual properties akin to Borderlands and Grand Theft Auto.