Immunotherapy can be said to be the second “revolution” in cancer treatment. Compared with targeted therapy, immunotherapy has a broader coverage of malignant tumors, and patients with effective treatment can even achieve long-term survival. However, immunotherapy is not effective for everyone, and if patients are not selected, the efficiency of treatment is only about one-fifth. In addition, immunotherapy, represented by immune checkpoint inhibitors, is not as immediate as targeted therapy and often takes a period of time to show anti-cancer effects. Therefore, immunotherapy is not a “miracle drug” although it has attracted much attention.