Warning: Spoilers for the Witcher book ending and Witcher 3 endings.
Netflix's The Witcher season 2 has Ciri take up residence in the Witcher stronghold and receive fighting training from them - but does she ever become a Witcher in any of the franchise's various books and games? The Witcher takes from both sources of inspiration for the show, balancing a mixture of author Andrzej Sapkowski's rich fantasy world, and the embellishments and scope that the Witcher games used to generate the huge success it had in its own right. This blended method ultimately works to provide both groups of viewers with an experience close to their previous experiences with the franchise - which is no easy feat, given that the games take place after the events of the books themselves.
In all three versions of The Witcher, Ciri is born magical powers as a result of the Elder Blood within her, which allows her to access other worlds - or Spheres - which makes her the target of many powerful factions who wish to use her abilities for their own means. Similarly, in all three different media, Ciri is assisted by Geralt and other Witchers, who both protect her and teach her how to protect herself. One place the books and games do differ, however, is how they explore Ciri's Witcher training.
The books see Ciri take on Witcher training, but technically never become a "true Witcher" as she never undergoes the Trial of The Grasses. However, it's clear she regards herself as a Witcher on some front, as translations of the final Witcher book - The Lady of The Lake - sees Ciri express that there must be something for a Witcher to do in the world she is in, suggesting she considers herself a Witcher still due to her upbringing and the aptitude it gave her for a career in monster hunting, though not fully confirming it. This is made a little more straightforward in the games, where one of Witcher 3's potential endings sees Ciri take up the Witcher profession officially and explicitly. While Ciri doesn't have the genetic mutation aspect that the rest of the Witchers do, it's fair to say in both versions that this doesn't necessarily exclude her from being considered one of them, as her powers allow her an arguably greater fighting prowess than any Witcher mutation, meaning there would have been no point to her undergoing the potentially deadly process.
Currently, Netflix's The Witcher appears to be more in line with the books in terms of source material, suggesting that it may use this more ambiguous ending for Ciri as a result. This said, the video game ending would also be a satisfying conclusion to Ciri's arc, and would allow for a potential spin-off or follow-up series focusing on Ciri's Witcher experiences and adventures, which would likely suit Netflix's goals better should they wish to keep expanding their Witcher universe.
Chances are high that Ciri's TV arc will also lead her into the Witcher profession, but it is worth noting that there are several other game endings the series could turn to for inspiration - though it seems highly unlikely that the series would decide to kill Ciri after making her even more of an integral protagonist alongside Geralt in The Witcher season 2. With such a wide scope of sources to take inspiration from, it's a sure thing that Ciri's future will be undeniably interesting - whether it leads to her becoming a Witcher or not.