CD4 and renal cell carcinoma: CD4+ T cells modulate the proliferation of RCC via the TGFβ1/YBX1/HIF2α signaling axis.[15] In many cancers, including RCC, high levels of activated CD8+ T cells are associated with better prognosis.[16,17] Regulatory T cells (Tregs), which secrete immunosuppressive cytokines, cause T cell dysfunction,[18,19] while tumor-associated macrophages may promote or suppress tumor development.[20,21] A variety of immune cells form a network of regulatory systems in tumors through complex interactions, thereby regulating cancer development and progression.