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. The gene discussed is PDCD1; the disease is pancreatic neoplasm.