Briefly, we classified responses to PD-1 blockade monotherapies into three groups: nonmixed responders (all metastatic lesions regressing and no presence of recurrences or new lesions); mixed responders (simultaneous regression and progression of metastatic lesions or new lesions); and nonmixed nonresponders (progressive metastatic lesions without tumor regression at any site). The gene discussed is PDCD1; the disease is neoplasm.