#$%^&*AU2020217358A120200903.pdf#####1003108248 ABSTRACT Provided are anti-PD-Li antibodies or fragments thereof The antibodies or fragments thereof specifically bind to the immunoglobulin C domain of the PD-Li protein. In various example, the antibodies or fragments thereof include a VH CDRi of SEQ ID NO: 1, a VH CDR2 of SEQ ID NO: 2, a VH CDR3 of SEQ ID NO: 3, a VL CDRi of SEQ ID NO: 4, a VL CDR2 of SEQ ID NO: 5, and a VL CDR3 of SEQ ID NO: 6, or variants of each thereof. Methods of using the antibodies or fragments thereof for treating and diagnosing diseases such as cancer and infectious diseases are also provided. -77-