They are like the animal Chameleon.
National Geographic:
Chameleons can stretch their iridophores to change the wavelength—and therefore the color—of the light they reflect. The reflected light from iridophores works in concert with the pigment in the chromatophores to produce the suite of brilliant blues, reds, and oranges seen in many chameleons.
https://www.nationalgeographic.Com/animals/article/color-change-camouflage-animals-explained