The effect of the neutralization of the PD-L1/PD-1 axis in pre-clinical cancer models is increased when combined with the MDSC inhibitor RGX-104 [290], the 1D11 anti-TGF-β antibody [330], or Galunisertib, an inhibitor of the TGBFR1 [331]. Here, PDCD1 is linked to cancer.