An early Days Gone comparison video has surfaced, comparing the recently-released PC footage to the game running on PS5.
While the video is said to compare the PS5 version of the game to the upcoming PC version, it should be noted that the PS5 is running the PS4 Pro version of the game through the consoles backward compatibility feature. And yes, Days Gone did receive a PS5 patch earlier but this only improved the games framerate and loading times. The PS4 Pro version of the game runs in checkerboarded 4K resolution.
Source: N4G PC Days Gone PC vs PS5 (PS4 Pro) Comparison Shows Minimal Differences