Why are the colors of many movies blue-green?

I think there are many reasons for this. Let's talk about it from a physical point of view. This gray level is called photos and videos. In order to make photos and videos look real and natural when selecting pictures and adjusting videos, post-production will adjust its gray level to balance its three colors of black, white and gray, especially when the gray level is dark, it will make the picture look real and natural.