@paulfree14 according to wikipedia, the Black Panther Party was created in october 1966.
https://en.wikipedia.org/wiki/Black_Panther_Party
Black Panther the comic book superhero that the film is about, first appeared in a comic book in july 1966.
https://en.wikipedia.org/wiki/Black_Panther_(comics)
If the two names are related, then it's probably the party / liberation movement that was named after the comic book superhero.