There is an anti-tumor immune mechanism in human body, which is like an “army” or “police” in human body. When the body temporarily loses its resistance under the attack of tumor, tumor immunotherapy can restore, stimulate or mobilize the immune system of the body to enhance its microenvironment, so as to control and kill tumor cells. Tumor immunotherapy can control and kill tumor cells by restoring, stimulating or mobilizing the body’s immune system to enhance its microenvironment and its ability to recognize and clear tumors. Tumor immunotherapy includes the following pathways: non-specific immune stimulation, secondary immune cell therapy, tumor vaccine, chimeric antigen receptor modified T-cell (CAR-T) therapy, and immune checkpoint inhibitors. Immune checkpoint inhibitors are a powerful tool for immune stimulation, tumor vaccination, CAR-T therapy and immune checkpoint inhibitors. (PD-1/PD-L1 and CTLA-4) expressed on the surface of lymphocytes, which plays an important role in the negative regulation of the immune response and prevents immune cells from mistakenly attacking the body’s own tissue cells. If immune cells mistakenly attack the body’s own tissue cells, causing excessive inflammation in tissues such as the skin, while killing many functional cells that should not be cleared, this can cause autoimmune diseases such as lupus erythematosus, which are incurable. Fortunately, these diseases are rare due to the existence of immune testing. In order to evade the immune system, cancer cells generally activate the immune response by activating PD-Ll (PD-Ll), which binds to PD-1 on the surface of cytotoxic T lymphocytes, thereby evading immune attack. However, this is not a function unique to the evolutionary emergence of cancer cells, but simply steals and amplifies a normal function of the body. Immune checkpoint inhibitors act on immune checkpoints (PD-1/PD-L1 and CTLA-4), blocking the immune checkpoints, blocking their signaling pathways, relieving the inhibition of cytotoxic T lymphocytes, restoring the normal proliferation and activity of cytotoxic T lymphocytes, and thus killing tumor cells, in short, suppressing immune suppression. Immune checkpoint inhibitors act on the immune checkpoints (PD-1/PD-L1 and CTLA-4), blocking the immune checkpoints, blocking their signaling pathways, relieving the inhibition of cytotoxic T lymphocytes, restoring the normal proliferation and activity of cytotoxic T lymphocytes, and thus killing tumor cells, in short, suppressing immune suppression. Currently, the immunosuppressive agents being investigated are the PD-l/PDL-1 and CTLA-4 signaling pathways. Antibodies that inhibit PD-l include nivolumab, MK-3475 (Pebrolizumab), lambrolizumab, MDX-1106; antibodies that inhibit PD-L1 include MPDL3280A and BMS-936559; and antibodies that inhibit CTLA-4 include ipilimumab. Preliminary clinical studies have shown that these drugs have good near-term efficacy in malignant lymphoma, non-small cell lung cancer, brain tumor, bladder cancer, pancreatic cancer, breast cancer, ovarian cancer, kidney cancer and other common malignancies, especially in malignant melanoma; more surprisingly, some patients can still achieve sustained tumor remission even after these drugs are discontinued. Immunodetection of the CTLA-4 and PD-l/PDCLl pathways, on the one hand, activates the specific recognition of tumor antigens by T cells, but at the same time, it also causes “misinjury”, i.e., autoimmune reactions by attacking its own antigens, with associated side effects, mainly including: skin adverse reactions (e.g., dermatitis, pruritus, rash, leukoplakia, alopecia). (such as dermatitis, pruritus, rash, white spots, hair loss, etc., the incidence is l2%-44%), gastrointestinal adverse reactions (such as vomiting, abdominal pain, diarrhea, colitis, hepatitis, etc., the incidence is 9%- 32%), infusion reactions (3%- l0%), endocrine disorders (such as hypothyroidism or hyperthyroidism, hypopituitarism, adrenal insufficiency, hormone level changes, etc., the incidence is 2%- 8%), interstitial Pneumonia and pulmonary edema (incidence of 3%-6%). Most clinical studies have reported the incidence of adverse reactions to be about 40% to 60%, with grade 3 – 4 reactions occurring in 3% to 20% of patients. Most of the adverse reactions are reversible, but a few of them are fatal, and these side effects require specific intervention. At present, the research of tumor immune-targeted therapy is flourishing, and immunosurveillance is a kind of severe and serious disease, if 2014 is the year of major breakthrough of tumor immune-targeted therapy, then 2015 will be the year that tumor immune-targeted therapy will become the mainstream anti-cancer therapy. However, there are many issues that need to be solved, such as the exploration of efficacy predictors, selection of treatment population, treatment duration, optimal treatment timing, whether to combine with chemotherapy, and immune detection, which is a very important factor in the future years.