Complex sentence: He returned to inpendent production with "Kramer vs. Kramer" in 1979, and in 1983, in collaboration with Sherry Lansing (then president of 20th Century-Fox), he started a production company, Jaffe-Lansing.
Split into simpler sentences: He returned to inpendent production with "Kramer vs. Kramer" in 1979. In 1983, in collaboration with Sherry Lansing (then president of 20th Century-Fox), he started a production company, Jaffe-Lansing.