Dulos et al.38 found that treating patients with advanced melanoma or prostate cancer with PD-1/PD-L1 checkpoint inhibitors can switch antigen-induced cellular reactivity to proinflammatory Th1/Th17 responses, such as enhancing the production of interferon-γ, interleukin (IL)-2, tumour necrosis factor α, IL-6 and IL-17, and decreasing the production of Th2 cytokines IL-5 and IL-13. This evidence concerns the gene IL17A and melanoma.