3DLUTS Greyed Out

I had this issue and I found it was because I was in CMYK mode under Image → Mode → CMYK Color
Setting it to RGB instead lets me re-add the Color Lookup adjustment layer and the option is no longer greyed out.

Problem is, the whole reason I wanted to use it was that importing RBG images into a Photoshop canvas setup with CMYK for printing purposes totally changes the color of the orginal image and I was trying to apply a 3D LUT to compensate (My greens were cooler in the CMYK mode for instance)