Introduction: It is not known whether patients with NSCLC who are hospitalized because of cancer-related complications are liable to benefit from salvage immunotherapy. Methods: This is a multicenter observational study including five centers, which involve all patients with advanced-stage NSCLC exhibiting a level of programmed death-ligand 1 (PD-L1) greater than or equal to 1%, having been hospitalized because of complications attributed to the evolution of the NSCLC, and having started pembrolizumab treatment during their hospitalization because of a risk of clinical deterioration in the short term. The analysis measured overall survival (OS) and the rate of discharge to home at 3 months. Results: The study included 33 patients, including 28 (85%) with metastatic NSCLC and 27 (82%) under first-line treatment. The main causes of hospitalization were deterioration of the general condition (52%), acute respiratory failure (18%), and an uncontrolled infection owing to the tumor (15%). A total of 20 patients (60%) had a performance status greater than or equal to 2 and 15 (45%) were under oxygen therapy. A total of 29 patients (88%) had a PD-L1 greater than or equal to 50%. Five patients (15%) started pembrolizumab in the intensive care unit. The median OS was 4.3 months (95% confidence interval [CI]: 0.9-not reached), and the 6-month and 1-year OS rates were 41.5% (95% CI: 27.5%-62.6%) and 32.6% (95% CI: 19.0%-55.9%), respectively. The home discharge rate at 3 months was 39% (95% CI: 23%-58%). Conclusions: Even when initiated in patients hospitalized for a life-threatening clinical deterioration, pembrolizumab seems to prolong the survival of certain patients with high PD-L1 NSCLC. Prospective, controlled data are necessary to confirm these results.