Immunohistochemistry is a form of pathological examination and is the gold standard for tumor diagnosis in clinical practice. Immunohistochemical examination is mainly applied to the detection of tumor pathological tissue sections, and is mainly used clinically for the diagnosis and differential diagnosis of difficult tumors. Through the immunohistochemistry report card, clinicians can clarify the tumor type of patients and select suitable anti-cancer treatment drugs and programs, so it is of great significance in clinical application. The immunohistochemistry report card will show the basic information of the patient, examination time, pathological images and pathological diagnosis results, which will indicate the type of tumor at the puncture site and different local immunohistochemistry indexes, and help to clarify the specific pathological type (commonly small cell carcinoma, adenocarcinoma, squamous carcinoma, etc.) and the primary site of the tumor. In the immunohistochemistry report form, different indicators are indicated by abbreviations, negative indicates “-“, positive indicates “+”, the more “+”, the higher the expression. The following indicators are commonly found in immunohistochemistry report card: 1) CEA: carcinoembryonic antigen, if the test result is positive, it usually indicates that the tumor type is more likely to be adenocarcinoma; 2) NSE: neuron-specific enolase, which exists in nerve tissue, so a positive test often indicates small cell lung cancer, neuroblastoma, etc.; 3) AFP: refers to alpha-fetoprotein, which is mainly used as a clinical test for primary hepatocellular carcinoma. AFP is mainly used as an indicator of primary hepatocellular carcinoma, and a positive test indicates a higher possibility of hepatocellular carcinoma; 4. CD10 is mainly used to mark acute leukemia and lymphoma, and is also sensitive to renal cell carcinoma and endometrial mesenchymal tumor; 5. S-100 protein is a neurogenic tumor marker, and is often used in the diagnosis of liposarcoma and nerve sheath tumor.