It is a series set in the Witcher Universe and stars Michelle Yeoh, that is all I need to know.

Netflix has this to say:

Set in an elven world 1200 years before the time of Geralt, Yennefer, and Ciri, The Witcher: Blood Origin will tell a tale lost to history: the creation of the first prototype Witcher, and the events that led to the pivotal Conjunction of the Spheres, when the worlds of monsters, men, and elves merged to become one. This four-part prequel series premieres on Netflix on December 25.

With Henry Cavil leaving the main series this miniseries might be the best way to keep the fans addicted to the series, not only that but it will be an awesome way to spend your time as you sit and digest your Xmas turkey.