Cancer immunotherapy takes advantage of the immune system to treat cancer. The checkpoint inhibitors have advanced the field of cancer treatment, but adoptive cell therapy and cancer vaccines also show promising results. The checkpoint inhibitors ipilimumab and later nivolumab/pembrolizumab have been standard therapy to patients with metastatic melanoma for several years. Today, the field is expanding, and other types of solid tumours have had checkpoint inhibitors applied to them, and more will follow. A portion of the patients develop immune-related adverse events, which should be handled by specialists.