Tumor heterogeneity manifests at multiple levels—between patients, across tumors within the same patient, and among individual cells within a tumor—shaping the biological and clinical trajectory of cancer. Liver cancer, in particular, exhibits pronounced heterogeneity, posing significant challenges for clinical management. Advances in multiomics profiling of clinically annotated patient samples have unraveled the complex molecular landscape of liver cancer, identifying key molecular subtypes. The integration of single-cell and spatial transcriptomic analyses further refines our understanding by capturing the diversity of transcriptional programs within tumors, offering a deeper, spatially resolved view of tumor heterogeneity.