PDCD1 and cancer: High expression of GUSB in HCC cells can lead to: 1) promoting cancer cell growth; 2) reducing PD-L1 expression, which is less responsive to anti-PD1 therapy; and 3) promoting immunosuppression, making HCC patients more inclined to a desert-type tumor immune microenvironment, which has a negative impact on anti-PD1 response.