The answer to that really depends upon the context in which you have found the expression!
I can make a stab at it but it could be inappropriate when read in context 🙁
Quality control review is simply a review exercise (hot or, more likely, cold) where a partner from another office of the firm, either in the same or a different country, or (if it’s a sole practitioner firm) a sole practitioner or a partner from a different firm of a similar size.
You have mentioned “individual partner review”. I have a feeling that this should be “independent partner review” Am I right?