Landau's family announced his death Saturday. No cause of death was given.
Landau's partnership with Cameron led to three Oscar nominations and a best picture win for 1997's "Titanic." Together the pair account for some of the biggest blockbusters in movie history, including "Avatar" and its sequel, "Avatar: The Way of Water."
"Jon Landau believed in the dream of cinema. He believed that film is the ultimate human art form, and to make films you have to first be human yourself," Cameron said in a lengthy statement posted by The Hollywood Reporter. "He will be remembered as much for his vast generosity of spirit as for the movies themselves.