Karelizumab immunotherapy, i.e. Karelizumab, is effective in lung cancer. Karelizumab is a humanized anti-PD-1 monoclonal antibody, which can enhance T-cell function and play an anti-tumor role, and can be used in combination with paclitaxel and carboplatin for the first-line treatment of locally advanced or metastatic squamous non-small cell lung cancer. The common adverse reactions of karelizumab include anemia, malaise, fever, hypothyroidism, pulmonary infection, hyponatremia, decreased appetite, cough, elevated transaminases, decreased platelets, hypokalemia, elevated lipase, etc.; it is contraindicated in patients who are allergic to the product, and caution is advised in the use of this product in allergic individuals. Patients should use the drug under the guidance of a physician’s visit, and if they feel unwell during the use of the drug, they should actively consult a doctor and follow the standardized treatment.