It would be possible with before-after shader (splitscreen). But note that most games do not preserve proper skin/sky tones, only game I know that has tip-top color grading is Uncharted 4 on PS4. So some adjustment is required prior to rest of the effects, to get colors right.
I would see the workflow like this:
• Making colors right (LUT)
• Before sampler
• Some ReShade color grading
• After sampler with preservation of sky-skin colors
Regarding skin tone, every human has the same pigment, melanin, so every skin tone has the same hue, just different levels of coloring. That is why on a Vectorscope there is only one line for a skin tone, no matter if you're color grading dark or light skin actor.
Here is screen-capture vectorscope showing that skin tone is the same.
It is using using FFMPEG, you can download the vectorscope script on my GitHub (you need to add FFMPEG bin folder into your system variables)
github.com/Fubaxiusz/Batch-tools/tree/master/FFMPEG%20scripts
It works nice if you have 2 monitors, on one you run game, and on the other, vectorscope.