CCAAT/enhancer-binding protein beta (CEBPB) is a critical transcription factor for cellular differentiation, inflammation, and metabolism. Recent studies have highlighted its dual role in tumorigenesis, functioning as both an oncogenic driver and tumor suppressor across diverse malignancies. This review synthesizes advances in understanding CEBPB’s contributions to tumorigenesis, tumor progression, immune evasion, and therapy resistance, emphasizing its potential as a cancer-specific molecular biomarker in cancer diagnosis, prognosis and treatment.