Antibodies targeting the PD-1/PD-L1 immune checkpoint axis enable T cell-mediated anti-tumor immunity, yet they have been largely ineffective in most PDAC patients (O’Reilly et al, 2019); even patients with mismatch repair-deficient PDAC tumors and presumably higher tumor mutational burden showed reduced efficacy compared with patients with mismatch repair-deficient colorectal and endometrial cancers (Le et al, 2017; Maio et al, 2022). This evidence concerns the gene CD274 and neoplasm.