Miramar has finally been released for PUBG on Xbox One
https://www.polygon.com/2018/5/24/17389828/pubg-miramar-map-xbox-one
Six months after its initial release — and after almost a month on the Xbox One test server — Miramar, the second map for PlayerUnknown’s Battlegrounds, has finally been released for the Xbox One version of the game.
The map arrived today as a part of PUBG’s spring update. The update also included all of the game’s Miramar-specific weapons and a variety of improvements to the Xbox One version’s load times, stability and optimization. The largest of these improvements should help to improve issues of buildings not fully loading when players land, and instability that led to the game crashing.