CD4 and neoplasm: Ex vivo flow cytometric analysis also showed that levels of NK, CD4+ T, and CD8+ T cells in the anti–PD-1 plus anti–CTLA-4 plus FTY720 group were significantly lower than those in the anti–PD-1 plus anti–CTLA-4 group without FTY720 (Figure 5G), further confirming the role of FTY720 in the inhibition of immune cell tumor infiltration.