CD8A and Granuloma: Since the PD-1HighCD8+ T cells were IFN-γ-producing effector T cells, the repeated injection of anti-4-1BB mAb induced granuloma formation in TDLNs, likely due to the excessive and sustained accumulation of IFN-γ-producing PD-1+CD8+ T cells and thus impaired sequential activation of CD8+ T cells in TDLNs.