To explore the frequency and contribution of HLA-A downregulation to immunotherapy resistance we analyzed 31 tumor dissociates derived from PD-1 PRE (n = 15, including 6 with RNA sequence data; Supplementary Data 1) and PD-1 PROG tumors (n = 16, including 10 from with RNA sequence data). The gene discussed is PDCD1; the disease is neoplasm.