The difference and correlation analyses revealed that the high-PD-L2 expression group was associated with more tumor-infiltrating immune cells, including CD8+ T cells, CD4+ T cells, B cells, macrophages, neutrophils, dendritic cells, regulatory T cells (Tregs), MDSCs, and natural killer T cells (NKT) (Figures 5B, C and Supplementary Figure 3). Here, CD4 is linked to neoplasm.