CD274 and hepatocellular carcinoma: Future research elucidate the subtype specificity of SphK1/SphK2 in different HCC types (e.g., virus-related vs. metabolism-related), continue to explore the core mechanisms of SphK2, validate its efficacy in primary HCC models, develop highly selective inhibitors to reduce toxicity, investigate optimized sequential treatment strategies, and promote clinical trials of combination therapies based on metabolism-immunity crosstalk (e.g., SphK inhibitors combined with PD-1/PD-L1 inhibitors).