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.