CD4 and urinary bladder cancer: identified that an EBV‐specific CD4 TCR‐T therapy can inhibit the growth of HLA‐DP5+ nasopharyngeal cancer in mice.[56] Later study also shows that CD4+ T cells derived from bladder cancers demonstrate the capability to lyse autologous tumors.[57] Several case reports indicate that transfusion of tumor‐reactive CD4+ T cells alone can induce significant anti‐tumor effects,[44, 58] underscoring their importance in human cancer immunity.