Overwatch has been through a proper draught when it comes to new heroes ever since Sigma was released but it appears that Blizzard will stop it soon as they released a new teaser, referencing Project Athena.
Blizzard released a new teaser that everyone hopes is about an upcoming hero since we haven't had one for almost eight months now. Sigma was the latest addition to the roster and the deranged scientist was released on 23 July 2019.
Hopefully, the teaser will indeed herald a new hero and one of the main indicators that it is so is the reference to Project Athena. In the teaser image , an Overwatch scientist named Mina Liao describes how her project was finally greenlit by Jack Morrison, now known as Soldier 76.
The project apparently focused on something that would bring humans and omnics closer so it is possible that the project is an omnic itself, albeit not one coming from an omnium. Other than the doctor herself, only "Athena" is mentioned by name, keep in mind that the moniker refers to a project and might not necessarily be the name of an actual entity.
Therefore, the name of the upcoming hero is not necessarily Athena but since it's possible it's an omnic, chances are this is a teaser for Echo, who was previously brought back by McCree.
It is not excluded that Dr. Liao will be the next agent to join the crew either, as the Recall cinematic from 2016 rolled over several agents that were not added back then. Sojourn is among them as well as the mysterious woman, shown on the picture below.
Athena is also the name of the AI that kept Winston company in the same animated short and it remains to be seen if she can assume a synthetic body and join the field.