Anti-programmed cell death-protein 1 (PD-1) ICI treatment is most effective in patients where T cells can recognize the tumor, and the highest response rates are found in patients with a higher density of tumor-infiltrating lymphocytes10–13, suggesting that BRAF/MEK inhibitor treatment could amplify the antitumor activity of anti-PD-1. The gene discussed is PDCD1; the disease is neoplasm.