CCL5 and neoplasm: Notably, regarding Fib_CD74+–CD4T_FOXP3+ MHC-I ligands (HLA-A/B/C) only exist in normal samples, while in the tumor microenvironment, Fib_CD74+ promotes the recruitment of CD4T_FOXP3+ through the binding of CCL5 to the CCR4 receptor (Figure 5G).