Immune checkpoint inhibitors (ICIs) have transformed cancer therapy, offering significant efficacy and a generally favorable safety profile. However, they are associated with a spectrum of immune-related adverse events (irAEs), among which pneumonitis stands out due to its relatively high mortality. This condition is characterized by nonspecific clinical manifestations and a broad differential diagnosis, often requiring the involvement of pulmonologists for accurate diagnosis and management. Given its potential severity, it is crucial for pulmonologists to be well-versed in recognizing and addressing checkpoint inhibitor pneumonitis (CIP). In this narrative review, we examine reported cases of pneumonitis in patients with various types of cancer treated with ICIs. The article explores the mechanisms of action of ICIs, the underlying pathophysiology of pneumonitis, associated risk factors, clinical presentation, diagnostic approaches, and current treatment strategies, intended to support pulmonologists in improving early detection and implementing evidence-based management of this potentially life-threatening complication.