CD4 and cancer: In addition, there was a negative association between CASP6 expression and the immune infiltration level of CD8 + T cells, NK cells, macrophages, monocytes, dendritic cells (DCs), neutrophils, and cancer-associated fibroblast cells, whereas showed a positive association with the abundance of CD4 + T cells, plasma cells, and tumor purity (Supplementary Figure S11B).