CheckMate 153 (NCT02066636) is a phase 3B/4 study assessing nivolumab in previously treated patients with advanced NSCLC. Eligibility criteria allowed enrollment of patients with poor prognostic features of advanced age or diminished Eastern Cooperative Oncology Group performance status (ECOG PS), which are typically underrepresented in or excluded from randomized controlled trials. Patients with stage IIIB or IV NSCLC and an ECOG PS of 0 to 2 with disease progression after at least one systemic therapy received nivolumab (3 mg/kg every 2 weeks) until progression, unacceptable toxicity, or consent withdrawal. The primary end point was the incidence of grade 3 to 5 select treatment-related adverse events (TRAEs). Among 1426 treated patients, 556 (39%) were aged 70 years or older and 128 (9%) had an ECOG PS of 2. The median treatment duration was 3.2 months. Across subgroups and the overall population, the incidences of select grade 3 to 5 TRAEs (6%–9%) and grade 3 or 4 TRAEs (12%–14%) were similar. One grade 5 TRAE was documented. The median overall survival time was comparable in the overall population (9.1 months) and patients aged 70 years or older (10.3 months) but shorter in patients with an ECOG PS of 2 (4.0 months). Patient-reported outcomes generally improved. Data from this large predominantly community-based study, which included patients aged 70 years or older and with an ECOG PS of 2, are consistent with registrational studies. As expected, the median overall survival for patients with an ECOG PS of 2 was lower than for the overall population but comparable with historical data.