After Overwatchs most recent PTR update, we saw some interesting new changes to the game, including a complete rework of Symmetra, along with other minor changes to the rest of the heroes.
However, the most exciting bit of the update came with the tweaks to the Horizon Lunar Colony map. It seems as if the developers are teasing the identity of their next Overwatch hero within the maps new changes.
Source: N4G PC Overwatch PTR Update Teases Next Hero, Hammond