Pathological section results of melanoma are malignant, and immunohistochemistry results are also malignant under normal circumstances; if immunohistochemistry benign results are present, it is usually an error in immunohistochemistry judgment. In addition, it may also be due to the heterogeneity of the tumor, in the same tumor tissue in different parts of the pathological results and immunohistochemistry is likely to be different. Melanoma is a tumor derived from the malignant transformation of melanocytes, which is highly malignant. The diagnosis of melanoma is mainly confirmed by histopathological examination and histopathological confirmation by biopsy of the pathology section. The pathological section result of melanoma is malignant, and if it appears immunohistochemically benign, the result may be misdiagnosis due to irregularity and incorrectness in the immunohistochemistry operation process, thus affecting the staining result. Heterogeneity of the tumor refers to the fact that the tumor undergoes multiple divisions and proliferation in the course of growth, and its daughter cells show alterations in molecular biology or genetics. The pathological section of melanoma is malignant and the immunohistochemistry is benign, it is also possible that the pathological results and immunohistochemistry are likely to be different in different parts of the same tumor tissue. It is suggested that patients keep good mood, can go to the local regular hospital for immunohistochemistry examination, and observe whether the result is benign or malignant.