Provided herein are combinations that include an HDACi and a PD-1 inhibitor that are useful for treating cancer, including reducing and/or preventing cancer metastasis. The combination is also useful for treating cancer that has been previously treated with a PD-L1 inhibitor.本文提供包括HDACi及PD-1抑制劑之組合,其適合用於治療癌症,包括減少及/或預防癌症轉移。該組合亦適合用於治療先前已用PD-L1抑制劑治療過之癌症。