Get latest articles and stories on Health at LatestLY. Immunotherapy has changed cancer treatment. Since the introduction of immunotherapy in 2011, the five-year survival rate in advanced melanoma, the most lethal form of skin cancer, has increased from less than 10% to more than 50%. Unfortunately, only approximately half of melanoma patients react to immunotherapy, and those who do not respond have a difficult future. Health News | Cancer Patients Who Do Not React to Immunotherapy Lack Crucial Immune Cells: Study.