PD-1-based immunotherapy has achieved great clinical success and has been approved for the treatment of various cancers.16 17 135 136 However, only a fraction of the patient population benefits from PD-1 blockade therapy.137 Even with the help of validated biomarkers, including PD-L1 and TMB, the response rate remains low (eg, approximately 40% in patients with NSCLC with PD-L1 expression in at least 50% of the cancer cells16). This evidence concerns the gene PDCD1 and cancer.