Moreover, we confirmed the clinical relevance of our findings by demonstrating that the Ptpn2 inhibitor PTP 9 sensitized melanoma tumors to anti-PD-1 antibody treatment in a mouse melanoma model, in part by promoting chemokine secretion and recruitment of CD8+ granzyme B-producing T cells to the tumor microenvironment. The gene discussed is PDCD1; the disease is neoplasm.