Produced by a Polish studio that seems to have done a ton of video game cinematics, not just for The Witcher.
Can't find any specifics from their website, but browsing job listings (https://platige.com/careers/) usually give an indication of what kind of tools they're using. Seems to be these as of today:
- Nuke
- Maya
- 3DS Max
- Unreal Engine
- Houdini
- ZBrush
Maya and Houdini is mentioned in a lot of them, but the cinematic doesn't have a lot of general VFX/destruction and such, so my guess is that they mostly used just Maya, rendered with Arnold and composited with Nuke. It's a very popular setup in the VFX industry and particularly at that time, before Unreal Engine was as useful as it is today.