120Hz video refresh rate: If you have a high refresh-rate monitor or television, the Xbox One can now support up to 120Hz.
Xbox Live and Discord integration: Xbox Live users can now sign into their Discord accounts. This doesn't allow you to take advantage of Discord's voice and text chat services, but it does allow Discord to show your Xbox One activity to your friends.
According to Murray, this update will bring PVP support, will feature dogfights, shared base building, races, team-based multiplayer or randomly encounters with other players.
Starting from the Discord app on PC or on a mobile device, you will see an option to link your Xbox account with your Discord account through the Connections tab under User Settings.
New button commands. Button commands have been updated throughout the Dashboard so that you can more easily find common options.
The premier feature of the May 2018 Xbox One update is added support for 120Hz displays. Now you'll be able to play online and explore the galaxies with company. With this update, the Xbox One S and Xbox One X can now output at 120 Hz when using 1080p or 1440p resolutions. "With the May update, you can trim your recent game captures directly from the Guide, so you won't need to switch to Upload Studio to make a quick cut to your saved clips".
As for the upcoming improvements on May Xbox One update, you can now browse through the new "Details" page on your family settings tab to easily check if your family is protected while using the Xbox One.
New button commands: The "View" button, or the "Select" button if you're nasty, can now rearrange items on the Home screen. Pressing the "View" button on the main tab of the Guide will also now display additional capture options. This allows users to switch from one game to another easily.