Complex sentence: Following the film's poor showing at the box office, Garbo's MGM contract was terminated, possibly by mutual agreement, and she never returned to filmmaking, leaving "Two-Faced Woman" as her last film.
Split into simpler sentences: Following the film's poor showing at the box office, Garbo's MGM contract was terminated, possibly by mutual agreement. She never made another film, leaving "Two-Faced Woman" as her last film.