This raises the possibility that STAT3 inhibitors may work best when combined with one or more of the novel, potent immune checkpoint inhibitors that target PD-1, PD-L1, or CTLA-4, inhibition of immunosuppressive factors, such as IDO, or treatment with chromatin modifiers that release SOCS genes from epigenetic repression in tumor cells. The gene discussed is PDCD1; the disease is neoplasm.