New job postings by Blizzard might be related to a new first person game they're developing. As of the moment, not much has been confirmed whether it is related to Overwatch or something new.
Overwatch has been a huge success for blizzard and the company is committed to improving its game. The developer has been constantly updating Overwatch, tweaking and improving the game . In its most recent update, blizzard has added a new character Sombra to its already large stable of characters in Overwatch.
It comes to a surprise then that blizzard is already looking for two software engineers to work on a robust first person engine for an unannounced project considering that the company already has a successful first person shooter.
Given blizzard's long intervals on realising their games, especially a new series, the developer already working on a new game at this stage would be unexpected.
Other than Overwatch, the only known first person shooter from the company was an unfinished project called Starcraft: Ghost which was revealed more than a decade ago. Development for that game was ongoing when it was suddenly stopped for an unannounced reason. The new job posting might be related to this if Blizzard plans to revive the project since fans were dismayed when it was found out that development was ceased.
A more likely scenario for the job openings would be an expansion for Overwatch. In its previous franchises, blizzard tends to release expansions to their games expanding the game's story and adding more features. Overwatch on the other hand, primarily a competitive online multi player, lacks a story mode to flesh out the characters.
To add to this, blizzard recently cancelled a graphic novel, detailing the events that lead to the game to act as a prequel. The graphic novel was supposed to tell the story of the Omnic Crisis and how the original Overwatch team was formed.
According to blizzard, the graphic novel was cancelled because the story has changed and expanded. Could this mean that the story for the graphic novel will now be used for the expansion for Overwatch which would explain the job opening? As now, all this is just are speculations and are yet to be proven. Regardless, we can still expect blizzard to continually support overwatch for many years to come.