Valve teams up with Overkill

After my post involving Valve's next game, this news decides to unleash itself.

the company Overkill, who made the game "Payday: the Heist", will team up with Valve to make a game that's a similar game to both Payday and Left 4 Dead. Hmn... sounds like a possible Left 4 Dead 3 with a Payday twist. No other comment was made.

So what do you think this game will be? a sequel or something new?