Immune checkpoint inhibitor (ICI) therapy represents a paradigm shift in the treatment of patients with locally advanced and metastatic lung cancer. Although immunotherapy generally has a more favorable safety profile when compared with chemotherapy, immune-related adverse events represent important, but incompletely understood, treatment-limiting complications associated with significant morbidity and mortality risk. Current guidelines for diagnosis and management are derived from consensus experience, highlighting that further prospective investigation in this area is needed. As ICI-related pneumonitis is a clinically and radiographically diverse toxidrome, clinical vigilance is important while treating patients with lung cancer.