PDCD1 and neoplasm: In addition, the blockade of different isoforms of TGF-β, including TGF-β1 and TGF-β2, has been shown to enhance tumour immunity through increasing the immune response from the Th1 population and the production of interferon gamma (IFN-γ), which is more efficient under programmed cell death 1 (PD-1) blockade [76].