CD4 and neoplasm: Indeed, lactate can contribute to tumour evasion by altering the metabolism and function of cytotoxic T lymphocytes (CTLs) [15], concurring to macrophage polarisation towards a pro‐tumoural M2‐like phenotype [16, 17, 18] and favouring an enrichment in CD4 immunosuppressive Tregs [11, 19, 20].