To search for potential regulatory points that may influence clinical response to anti-PD-1 immunotherapy, we explored the relative mRNA expression of 15 SUMO machinery components in PBMC from 105 lung cancer patients (53 responders and 52 non-responders) for 9 weeks after anti-PD-1 immunotherapy (Figures 1A–C; Supplementary Figures 1, 2). The gene discussed is PDCD1; the disease is lung cancer.