Since NKTR-214 alone has little effect, it has been speculated that NKTR-214 and immune checkpoint inhibitors (anti-PD-1, anti-CTLA-4) have a synergistic effect in resisting tumor, and this has been strongly supported in some preclinical (37, 38) and clinical experiments (Table 1). The gene discussed is PDCD1; the disease is neoplasm.