Intrahepatic cholangiocarcinoma (ICC) is a highly malignant primary liver tumor with a poor prognosis. In recent years, research on ICC has surged, with the number of related publications in the PubMed database increasing annually. However, research progress has mainly focused on molecular mechanisms and systemic therapy, while advancements in surgical treatments for ICC have been relatively slow. Traditionally, ICC has been commonly regarded as a uniform disease entity in clinical practice. There are considerable controversies regarding ICC, including its epidemiological characteristics, clinicopathologic features, and molecular biology traits. Appropriate classification is the cornerstone of ICC research. This paper reviews the relevant literature at home and abroad to address its heterogeneity from different perspectives on the controversies surrounding ICC.