Provided herein are compositions comprising coformulation of anti-PD-L1 and anti-CTLA-4 antibodies, or antigen-binding fragments thereof, and methods of making and using such compositions. In various aspects, stable coformulations of the anti-PD-L1 antibody durvalumab (MEDI4736) and the anti-CTLA-4 antibody tremelimumab are provided.