This is a prospective, observational, multi-center, real-world study evaluating the effectiveness and safety of Toripalimab (a PD-1 inhibitor) as first-line treatment for patients with extensive-stage small cell lung cancer (ES-SCLC). The primary objective is to assess real-world progression-free survival (rwPFS). Secondary objectives include evaluating real-world objective response rate (rwORR), disease control rate (rwDCR), overall survival (rwOS), and safety. Approximately 1200 patients from multiple centers in China will be enrolled and followed according to routine clinical practice. Data will be collected from medical records and follow-up visits.