The Witcher 3 is a gorgeous game, and for the past five years one modder has been working tirelessly to update its textures to help keep it that way. Called The Witcher 3 HD Reworked Project, this is one of the best mods you can get for the Witcher 3, and its upcoming 12.0 update makes it even better by improving the quality of textures on NPC clothing and faces.
The video above speaks for itself—but I'd recommend watching it on a screen capable of at least 1440p to really notice the difference. The sole person on the project, Halk_Hogan_PL, has upgraded a lot of the textures, like the bits of leather on a piece of armor for example, to 4K resolution, resulting in much more lifelike and sharper textures.
Whether you'll notice the difference while chopping a bandit in half will really depend on you and your hardware, though. If you're only playing The Witcher 3 at 1080p, a lot of this detail won't be noticeable unless you get really up close and personal with NPCs. But at higher resolutions (especially 4K), you should definitely notice the difference.
The good news is that update 12.0 will rework a lot of Geralt's equipment too. There's a short tease at the end of the above video, but Halk_Hogan_PL says another video focusing entirely on improvements to Geralt's textures are on the way. When update 12.0 will be released, though, isn't clear. Hopefully soon.
The current version of The Witcher 3 HD Reworked Project can be downloaded here.