PDCD1 and neoplasm: Treatment with a murine PD-1-targeted IL-2 variant antibody complex (PD1-IL2v), which is composed of a high-affinity anti-PD-1 antibody fused to an IL-2 variant with abolished binding to CD25 (IL-2Rα), can increase the expansion of tumor-antigen-specific CD8+ T cells, inhibit the immunosuppressive function of Tregs, and improve the antitumor efficacy of radiation therapy [102].