PDCD1 and prostate neoplasm: An example of this is the success of the combination of Vγ9Vδ2 T cells and therapeutic PD-1 monoclonal antibodies (mAbs) that enhanced the cytotoxicity of Vγ9Vδ2 T cells.26–28 In another preclinical experiment of PC-3 prostate tumors treated with Vγ9Vδ2 T cells, anti-PD-1 mAbs also enhanced the immune activity effectiveness of Vγ9Vδ2 T cells and reduced the tumor volume of tumor-bearing mice to almost zero after 5 weeks.29