During a panel at PAX East, PlayerUnknown himself Brendan Greene confirmed that PUBG's second map will be coming to Xbox One next month. The desert map Miramar has been available on PC since December, with the team working hard to get it ported to the Xbox One version, which follows a different content and balance roadmap. While the PC version launched into 1.0 and out of early access with the release of Miramar, it's not clear if same will happen with the Xbox One version. The Xbox One version of PlayerUnknown's Battlegrounds released in December last year.
UPDATE 5/18/18 - Miramar coming to Xbox One PUBG on May 24.