STAT1 and neoplasm: In addition to extensive studies on how the PD-1-PD-L1 axis allows tumors to escape from the immune system, a recent study showed that the eIF4F–STAT1–PD-L1 axis promotes PD-L1 expression on tumor cells and inhibitors of eIF4A (the RNA helicase component of eIF4F) could be developed as anticancer drugs, because inhibition of eIF4A downregulates PD-L1 expression on tumor cells [25].