More than any other character, Mr. Spock has been the poster child for the Star Trek franchise, starting the first pilot and continuing all the way up to the ongoing Star Trek: Strange New Worlds series. Leonard Nimoy brought him to life so marvelously, that for a long time the idea of another actor playing the role was inconceivable. Even the Kelvinverse movies brought Nimoy in for a cameo when Zachary Quinto took over the role, giving the new actor his blessing while establishing firmly that they are two distinct variants of the character.
Source：https://www.cbr.com/why-spock-is-different-strange-new-worlds/
