CSF2 and hepatocellular carcinoma: When combined with PD-1 inhibitors, the choice of targeting strategy significantly affects combination efficacy; in a hepatocellular carcinoma model, granulocyte-macrophage colony-stimulating factor (GM-CSF)-carrying targeted viruses combined with anti-PD-L1 therapy increased objective response rates from 24% to 61%, though exclusively in PD-L1-positive subgroups [36,99].