Anton thank you for your answer!
But when scene take place outdoors, without set and location design, cold overcast day, and you need to make image very cold blue , so you push blue into the image and the skin gets also blue, too blue, or opposite when you shoot outdoors on sunny day, and you want further enhance this warmth by making a warm yellow hot sunny look, you push yellow orange into image, and skin gets too warm. So you need just control on skin to pull some coldness or warmth back. Im not talking about separating skin from the wall (background), but asking how you deal with strong color casts looks (very green look, or very blue, or very yellow look), but also to leave (protect)skin natural in that particular environment, cold blue environment or warm yellow environment, without being skin too blue or too orangy-yellow? But also not too overprotect it, so it looks natural in cold blue environment or in warm yellow environment for example.