CD4 and neoplasm: Within the tumour‐infiltrating lymphocytes, Tregs are the most numerous population and can suppress T helper cell and CTL responses (El Andaloussi and Lesniak, 2006; Mirzaei et al, 2017), while CD8+ and CD4+ T cells are exhausted (Thorsson et al, 2018; Woroniecka et al, 2018).