In December 2020, ZeniMax Online (developers of The Elder Scrolls Online) revealed that they had started a new studio in San Diego that is going to work on an unannounced AAA title. But it seems like this isn't the only secret game they are currently developing, as they now post on Twitter that they are hiring people for "multiple unannounced projects".
There are currently 45 open positions in basically all stages of game development, so unfortunately, there are no clues of what to expect, but at least it's good to know that there are plenty of games coming from ZeniMax Online.
ZeniMax Online was one of the many developers Microsoft got when they announced their intention to buy ZeniMax last year (together with others like Bethesda, Id Software, Arkane and Machine Games). Basically, expect these upcoming ZeniMax Online games to show up for PC and Xbox, and also to be included with Xbox Game Pass.