Among patients with PD-L1 ≥ 50%, the ICI-chemo group showed a greater trend toward longer PFS compared with the chemo group (16.9 vs. 4.0 months; HR 0.11, 95% CI, 0.01-1.05).<h4>Conclusions</h4>Adding ICI to platinum retreatment may be an effective option for patients with NSCLC who relapse after perioperative chemotherapy, particularly in those with PD-L1 expression ≥ 50%. Here, CD274 is linked to non-small cell lung carcinoma.