With a median follow-up of more than 2.5 years, sintilimab added to chemotherapy improved OS in patients with advanced, nonsquamous NSCLC. The median OS was 24.2 months with sintilimab and 16.8 months with chemotherapy alone. Nearly half of patients in the chemotherapy-only arm crossed over to receive sintilimab after disease progression. When the data were adjusted for the crossover effect, the OS benefit derived from sintilimab was more pronounced.