https://www.techradar.com/news/xbox-one-x-and-one-s-get-a-pc-style-upgrade-with-radeon-freesync-support

Xbox One X and One S owners will soon be able to enjoy a luxury that PC owners have had for the last three years. AMD and Microsoft have announced that the two higher-end Xbox One consoles will both get Radeon FreeSync support from Q2 this year. 

FreeSync reduces the amount of screen-tearing and mismatched frames in games, reducing 'stuttering' and providing a more seamless and smooth gameplay experience. To take advantage of this, gamers will need a compatible FreeSync display that's connected to their console via HDMI.