PRF1 and neoplasm: These transferred CD4+ T cells can facilitate tumor regression by aiding CD8+ T cells or exerting direct anti‐tumor effects through secretion of T helper 1 (Th1) cytokines like IFN‐γ and TNF‐α, or directly targeting MHC II‐expressing tumor cells via granzymes and perforins.[59, 60, 61] Moreover, Bastian Kruse et al.