CD274 and hepatocellular carcinoma: These computational findings were validated through <i>in vitro</i> experiments, immune infiltration assessments, and single-cell RNA sequencing analysis.<h4>Results</h4>Our analyses demonstrate that METTL1 is markedly upregulated in HCC, driving a reprogramming of nucleotide metabolism that modulates the expression of key immune checkpoints, including PD-L1 and CTLA-4.