It can be a slight retouch if, for example, the render has gone to magenta and we want it back or we simply want to touch the brightness and contrast or saturation of certain colors of the scene.
Or, being more ambitious, to turn the complete production or some of the sequences towards a general tonality colder or warmer.
Take for example Fargo, although any of the current Nor Noir TV series are also good examples. It is obvious that the plot runs in a very cold territory. It’s appreciated by the continuous presence of snowy landscapes, even icy. The costumes of the characters highlight this environment. The mist that comes out of their mouths when they speak also does. Light of these latitudes is a key factor in creating this hostile environment.
But it is no accident to use color correction in cases like this. Without going into details, the color palette and its shades were well thought out: cold, cool colors.
The plot needed it and the correction of color helped to convey that feeling of white desert, of hostility, of violence, of discomfort.
The best recommendation to understand all this I have told you now is to see this video: “Color In Storytelling”. It is explained wonderfully with very recognizable examples of images from the history of cinema that we all remember. I invite you to, after seeing it, in the next movie you see, you notice this visual aspect.