Blizzard is working on an "unannounced project that utilizes a robust first-person engine," according to two job listings on the company's US careers site.

The listings are for two lead software engineers, both specifically preferring workers with experience working on first-person games.

To date, Overwatch is the only first person game Blizzard has ever developed. It's not clear whether the project these job listings refer to is an expansion or sequel to Overwatch, or a new game altogether. Other series from the developer include World of Warcraft, StarCraft, Heroes of the Storm, and Hearthstone.

This isn't the first time Blizzard have advertised jobs for unannounced projects. Earlier this year, the company was after someone to lead the next Diablo project. In 2015, meanwhile, it was hiring an art director for an "unannounced project" in the Diablo universe.

Overwatch's latest big update is the introduction of Sombra, a new character capable of hacking other players' abilities. The base game, meanwhile, was very popular here at GameSpot--critic Mike Mahardy called it a "brilliant shooter," awarding it a 9. For more, check out our full Overwatch review.