However, there is emerging evidence of autoimmune conditions such as type 1 diabetes, fulminant myocarditis and pneumonitis developing as potential immune-related adverse events (irAEs) due to anti-PD-1 therapy [2,3]. These toxicities are thought to result from the inhibition of the PD-1/PD-L1 pathway, which normally suppresses autoreactive T-cells. Here, PDCD1 is linked to pneumonitis.