CD4 and neoplasm: Having a predominately T helper type 1 (Th1) cytokine phenotype, tumour‐specific CD4+ T cells may provide help in the proliferation, differentiation and maintenance of CD8+ T cells in the tumour microenvironment and act in synergy with local CD8+ T cells to control tumour growth, even though they may not necessarily have direct cytotoxic abilities 13, 14, 15, 16.