so this is based off my memory so there could be inaccuracies.
but what i’ve heard is that pink is the result of your brain registering a color because of specific color cones being activated but that your brain knows it’s not actually that color and so it fills it in with pink.
It’s a real color (as real as colors can be, which is not very). It’s not a spectral color, you won’t find it on the rainbow. It’s actually the result of your red and blue cones being activated together.