According to the  director, they are aiming for two different modes  for the game on the  PS4 Pro, just like it was the case for Square  Enix’s Rise of Tomb  Raider. The first mode is native 1080p with  unlocked frame rate that  targets 60 fps. The second option is upscaled  4K using a rendering mode  (e.g checkerboard rendering) with locked 30  fps.
The developers have managed to make the game run at 40 to 50 fps on the  PS4 Pro in its current state. They have plans to release a patch in  December that will further improve and stabilize the frame rate on PS4  Pro so it runs closer to 60 fps.