The reported incidence of pneumonitis in patients with advanced NSCLC treated with anti‐PD‐1 monotherapy is 3%–5%,3, 4, 5, 6 whereas the frequency escalates to 5%–7%1, 2 in those receiving to ipilimumab plus nivolumab, reaching over 10% in the Japanese population.7 Here, PDCD1 is linked to non-small cell lung carcinoma.