The Star Trek saga spans six decades and over 800 hours of storytelling on television and in film. While the universe created by Gene Roddenberry is vast and dynamic, the Klingons have appeared in every iteration of the franchise. Yet, since their debut in Star Trek: The Original Series in 1966, the Klingons' character design has changed over time. From regular humans with brown makeup and stylized facial hair to the intricate alien prosthetics on the characters in Star Trek: Discovery, there's more than one way to skin a Klingon.
Source：https://www.cbr.com/star-trek-klingon-design-explained/
