As shown in Figure 3B, tumour samples (PT and M) were enriched in exhausted CD4+ T cells and Tregs, whereas the proportion of CD4+ TEM, CD8+ TEM and cytotoxic CD8+ T cells was slightly reduced in M compared with the level in NT as expected,46 indicating a suppressive immune microenvironment created during tumour progression and metastasis. Here, CD4 is linked to neoplasm.