According to the developers, this is a completely new class that has not yet been seen in the series.
At BlizzCon 2023, the Vessel of Hatred expansion for Diablo IV was announced. It will continue the plot of the original game and, according to the authors, will become even darker: gamers will go to the new region of Nahantu and challenge Mephisto. Among other things, the DLC will feature a completely new class that has not previously been seen in the Diablo series.
The expansion will be released in the second half of 2024. Blizzard promises to talk about it in more detail next summer.