Bethesda Game Studios is actively working on two previously revealed projects in the form of Starfield and The Elder Scrolls 6. However, it seems as though the studio behind classic games like Skyrim and Fallout may be working on a third, unannounced project. What that project is remains to be seen, but a recently discovered job listing does indeed suggest that Bethesda is working on something besides what's already been announced.
As spotted by Pure Xbox, ZeniMax is hiring a Server Engineer for Bethesda Game Studios to work on an unannounced game. The job listing doesn't give any clue as to what the game is, but since Starfield and The Elder Scrolls 6 have already been announced, it seems likely that the job is for a third project that's in the works. Unfortunately, it's impossible to say with certainty what exactly Bethesda is working on, and so any guesses are purely speculation at this time.
The job listing is specifically for Bethesda's office in Texas, which previously worked on Fallout 76. This could indicate that this unannounced project is not being handled by the "main" Bethesda Game Studios team. For those who may be unaware, Bethesda's Austin location has mainly been focused on online functionality, so it's possible that this project is a new, online multiplayer game based on one of the company's franchises. Then again, Bethesda's Austin studio could instead be providing support to the main team for a game that they're working on.
But again, all of this is just speculation. There is very little to go off of when it comes to this newly discovered job listing, and it's unlikely that fans will learn anything new anytime soon. Starfield isn't even out yet, and The Elder Scrolls 6 is expected to launch after Starfield. Those two games should do a lot to occupy Bethesda's time for the next decade or so, with maybe one other new game from the studio to release in the latter half of the decade.
As far as Starfield goes, Bethesda fans may actually get to play the game sooner rather than later. Starfield's release date is rumored for late 2021, with the game expected to get a full unveiling at Microsoft's E3 2021 press conference. Whether or not that comes to pass remains to be seen, but with E3 right around the corner, Bethesda fans don't have much longer to wait.
The Elder Scrolls 6 release date will likely be years from now, well after Starfield launches, and so fans of the studio shouldn't expect to learn more about any of its other future projects for some time.