PPT1 and hepatocellular carcinoma: Investigations in peripheral tumor types, such as melanoma and hepatocellular carcinoma, revealed that late-stage autophagy inhibition with chloroquine, which was shown to act as an inhibitor of palmitoyl-protein thioesterase 1 (Ppt1) (74–76), reverses the immunosuppressive nature of tumor-associated macrophages and thus increases the efficacy of T-cell targeted PD-1 therapies (28, 76).