Cameo appearance
A cameo role or cameo appearance (often shortened to just cameo) is a brief appearance of a known person in a work of the performing arts, such as plays, movies, video games and television. Such a role does not have to be an actor: short appearances by movie directors, politicians, athletes, and other celebrities are common.
Some examples would be Alfred Hitchcock briefly appearing in some of his movies or Stan Lee always briefly appearing in Marvel-related movies or Salman Khan's apperance in Pathaan.
Cameo Appearance Media
The 1945 psychological drama film Spellbound features a cameo by director Alfred Hitchcock in which he exits an elevator. Hitchcock is known for his small cameos in his films.
Stan Lee was well known for his cameo appearances throughout most of the Marvel films.