A cosmetic change on the Overwatch PTR might hint at the next new map being introduced to the game.
It’s possible, however, that amid the various gameplay changes, a relatively minor change to one of the maps might offer the first hint at an upcoming map.
In the first offensive spawn room on Numbani, an update has been made to the décor. On the live servers, the back wall is covered in posters depicting four locations for which there are in-game maps: King’s Row, Volskaya, Temple of Anubis, and Hanamura.
On the PTR, however, the Temple of Anubis poster has been replaced, with the new poster reading “Viva Cuba, Havana”. The same swap has been made in the travel agency side room.
As u/Karahe points out, Baptiste’s bio reveals that “Guided by his innate desire to help people, Baptiste chose the path of a combat medic and served in an elite branch of the Caribbean Coalition’s special ops.”
Given that Cuba is located in the Caribbean, a Havana map would certainly fit nicely alongside Baptiste’s addition to the game.
It’s also very possible that Havana might be the location for the next story mission added by the upcoming Overwatch Archives event, which is expected to arrive in early April. The 2018 iteration of Archives, Retribution, also added a new map, Rialto, based on the Blackwatch mission that took place there.
This isn't the only hint about potential future maps for Overwatch. After Paris, the most recent addition to the map pool, was revealed, players noticed that three of the five locations marked on a graphic in Soldier 76's origin story were now in-game maps, suggesting the remaining two - Seattle and Rio de Janeiro - as possible future maps.
This change to Numbani, however, suggests a more immediate reveal.Blizzard have often used small map changes like this to tease future content, with changes made to Horizon Lunar Colony ahead of Wrecking Ball’s arrival, for instance, and an update to the Route 66 payload foreshadowing the reveal of “Echo” in the “Reunion” animated short. This latest change, therefore, is unlikely to be insignificant.
This also isn’t the first time this very room has been updated ahead of new content. The destruction that can be seen in the room on the live servers wasn’t there when Overwatch launched, but was added ahead of the release of Orisa, whose creation was precipitated by an attack on Numbani by Doomfist.