However, high PD1 expression leads to CD8 + T cell exhaustion, and an increase in PD1 + CD8 + T cells and a decrease in TNFα + /IFNγ + CD8 + T cells due to ABHD17C in the pancreatic cancer microenvironment can promote the immune escape of tumor cells and inhibit immune killing. This evidence concerns the gene PDCD1 and familial pancreatic carcinoma.