PDCD1 and neoplasm: As SEMA4D was found to be associated with T cell exhaustion in the single-cell analysis shown in Figure 2, we further investigated the correlation between SEMA4D expression and CD8+ T cell exhaustion checkpoints (e.g., TIGIT, LAG3, TIM3, and PD1) in the 13 highly expressed SEMA4D tumor types (Figure 6).