Immune-related adverse events were different between anti-CTLA4, anti-PD(L)-1 and combination therapy (p = 0.028), with pneumonitis being more common in patients treated with anti-PD(L)-1 (44% versus 0%, p = 0.03), whereas colitis was only diagnosed in patients treated with anti-CTLA4 or combination therapy (0 versus 36%, p = 0.027) (Additional file 2: Figure S2 panel C). Here, CTLA4 is linked to pneumonitis.