CD44 and neoplasm: Previous studies have shown that Macro_C1QC inhibits CD8+ T cell function through C1q complement signaling and lipid metabolism reprogramming mediated by FABP5 (44), while Macro_SPP1 exacerbates T cell exhaustion and promotes tumor metastasis via SPP1-CD44, hypoxia-HIF-1α axis, and MIF signaling (45, 46).