PDCD1 and neoplasm: This likely explains that the average response rate and average clinical benefit rate of γδ T-cell immunotherapy have failed to meet expectations in many clinical trials.22 In addition, inflammatory γδ T cells can indirectly inhibit αβ T-cell activation through the PD-1/PD-L1 axis, leading to a decrease in tumor-infiltrating lymphocytes.23 All the above checkpoint toxicity exacerbates the plasticity of effector T cells.