PS4 Firmware 5.50 introduces system-wide supersampling for PS4 Pro
The PlayStation 4 Pro console is capable of delivering images up to a 4K resolution, but a lot of titles that are enhanced on PS4 Pro don't offer improvements for gamers playing on a 1080p screen. With supersampling, the image is rendered at a higher resolution (such as 4K) and then downscaled to a lower resolution such as 1080p. This is an effective method to reduce aliasing and improve the overall image quality.
The feature was first reported by users on the Resetera forum, who shared screenshots of the new functionality. PS4 Pro owners with the 5.50 Beta firmware installed can enable supersampling mode in the settings. The company does emphasize that results of supersampling can differ depending on the supported games. Microsoft's Xbox One X - PS4 Pro's main competitor - supported system-wide supersampling at launch.
The system-wide supersampling feature is particularly useful for PS4 Pro owners playing on a Full HD screen, as many of the PS4 Pro enhanced games did not support supersampling on their own. Examples of this are Assassin's Creed: The Ezio Collection, Dishonored 2 and Metal Gear Solid 5: The Phantom Pain.
At the moment, it's still unclear when the new firmware will be available to all users.