CTLA4 and neoplasm: In summary, the integration of bulk RNA sequencing and single-cell RNA sequencing technologies has significantly advanced our understanding of the tumor immune microenvironment, enabling the prediction of predictive biomarkers such as PD-L1 and IFN-γ response signatures, as well as the characterization of immune cell heterogeneity and exhaustion markers like PD-L1 and CTLA-4.