With the approval of the first Immune-Checkpoint Inhibitor (ICI), a new category of side effects has emerged - immune-related adverse events. ICI-related pneumonitis is a rare, but potentially fatal side effect, with an incidence of 3–10% in different trials involving ICI, with greater incidence in patients with non-small cell lung cancer (NSCLC). This is the largest histopathologic study to date (n = 16) characterizing non-neoplastic lung tissue from ICI-treated patients, in mono- or polytherapy regimens.
