After teasing it on its official Witcher Twitter account, CD Projekt Red has confirmed it is indeed working on a new Witcher game.
The game will be developed on Unreal Engine 5, rather than CD Projekt Red's own REDengine. This comes as a surprise but is the result of a multi-year partnership between CD Projekt Red and Epic Games. CD Projekt Red was also keen to note that this does not mean that the game will be exclusive to the Epic Games store, and the partnership contract "covers not only licensing, but technical development of Unreal Engine 5, as well as potential future versions of Unreal Engine, where relevant".
Unfortunately, CD Projekt Red was not ready to talk about the details of the game or its release date, and it is still not clear if it will follow the same storyline or be a completely new story, which could be what the teaser means with "A new saga begins" tagline.
In any case, we are looking forward to more information from the developer as the series has been one, if not the most popular game released.