The ORR was significantly higher in patients in the IO+C group (45% vs. 25%, p < 0.01). The median PFS was 6.4 months for patients in the IO+C group compared to 2.8 months for patients in C group (HR: 0.41, 95% confidence interval [CI]: 0.20-0.82, p < 0.01). The median OS was significantly longer in the IO+C group than the C group (OS: 12.8 vs. 10.5 months, HR: 0.39, 95% CI: 0.19-0.80, p < 0.01). In subgroup analysis, patients of both sexes, age ≤ 65, bone or adrenal metastasis, exon19 del mutation, and third-line treatment obtained more OS benefits from immunotherapy....Our study provides the clinical evidence of favoring immunotherapy plus chemotherapy in NSCLC patients after progression on osimertinib.