This application relates to CD80 (B7-1) extracellular domain (ECD) polypeptides and CD80-ECD fusion molecules and their use in treatment of cancer, both alone and in combination with other therapeutic agents, such as immune stimulating agents such as PD-1/PD-L1 inhibitors.本申請案係關於CD80(B7-1)胞外域(ECD)多肽及CD80-ECD融合分子以及其單獨及與諸如免疫刺激劑,諸如PD-1/PD-L1抑制劑之其他治療劑組合用於癌症治療中之用途。