PDCD1 and neoplasm: In a mouse model where anti-PD-1 treatment was ineffective, the combined use of SRK-181-mIgG1 (specifically inhibiting TGF-β1) and anti-PD-1 antibody resulted in an increase in intra-tumor CD8+ T cells and a decrease in immunosuppressive myeloid cells, indicating an anti-tumor effect [80].