Blizzard has revealed that it is planning on releasing an update for the Xbox One version of Overwatch. The update will feature support for 4K rendering when playing on the Xbox One X.
The new update for the Xbox One version of Overwatch is currently being developed and does not have an official release date yet. It is expected to be released in early 2018.
Whether the PlayStation 4 version of the game will also be getting 4K resolution rendering support is still unknown. The PC version already supports 4K resolution rendering since the game was first released in 2016.