PDCD1 and neoplasm: TGF-β might be the main driver of immune cell exclusion in several tumours.99 Numerous clinical trials are testing the safety and anti-tumour activity of the combined blockade of TGF-β using small molecules, such as galunisertib, or antagonistic monoclonal antibodies, such as fresolimumab, with PD-1–PD-L1 such as nivolumab or durvalumab (NCT02423343 and NCT02734160).