This is a trick that can sometimes throw interesting results in your renders. The effect is having a cinema look by boosting the contrast/exposure and desaturating.
Instead of tweak the values involved, just follow this steps:
1. Duplicate the image layer.
2. Desaturate the duplicated one.
3. Put the desaturated layer on top.
4. Switch its blending mode to overlay.
You can adjust the strength of the effect by tweaking the levels of the desaturated layer or just with the opacity control. Here is the result in a random image: