In the adaptive and innate immune systems, malignant tumor cells escape recognition and destruction via the HIF-1 in the hypoxic TME, where HIF-1 signaling suppresses immune attack by triggering increased expression of immune checkpoint molecules and tumor immune evasion factors, such as interleukin (IL)-10, vascular endothelial growth factor (VEGF), TGF-β, prostaglandin E2 (PGE2), and PDL-1/programmed death-1 (PD-1) [22]. The gene discussed is PDCD1; the disease is neoplasm.