Lately, some studies have reported that anti-PD-1/PD-L1 is effective against melanoma,3, 4, 5 non-small cell lung carcinoma (NSCLC),4,5 renal cancer,5,6 Hodgkin lymphoma,5,7,8 etc. However, the efficacy of immune checkpoint inhibitory therapy is not as high as expected in several types of cancers. The gene discussed is PDCD1; the disease is melanoma.