Clinical trials on cytotoxic T Lymphocyte antigen 4 (CTLA-4) blockade, programmed cell death-1 (PD-1)/ PD-L1 blockade, and dual checkpoint inhibition have poor efficacy, which may be related to the highly immunosuppressive tumor immune microenvironment (TME) of PDAC5,10–12. This evidence concerns the gene PDCD1 and neoplasm.