Hematoxylin and eosin staining is simple and one of the most important techniques in pathological diagnosis. However, it cannot provide complete information about the disease of a patient. Immunohistochemical staining (IHC) is an important method for demonstrating the distribution of a certain molecule or antigen in tissues using specific antigen-antibody reactions. It is used in routine diagnostic work and research to explore biomarkers. In this review, I aim to provide an adequate interpretation of the results of IHC and pathological diagnosis for clinicians.