https://wccftech.com/xbox-one-x-natively-support-1440p/

1440P (2560×1440) is kind of the stepchild when it comes to current display resolutions. Caught in the middle between the dominant FullHD (1920×1080, or 1080p) and 4K (3840×2160, or 2160p) resolutions, 1440P is only popular among PC gamers who can enjoy incredibly high refresh rate with the latest panels.

However, there’s a fair number of gamers using monitors to play on consoles. There’s good news coming that way, as Microsoft’s Kevin Gammill, Partner Group Program Manager at Xbox, confirmed that the Xbox One X will be able to output natively at 1440P via HDMI.