Kaplan-Meier curves of (A) PFS and (B) OS for patients with MSI/dMMR gastrointestinal cancer in the anti–PD-1/PD-L1 weighted group and chemo-anti–PD-1/PD-L1 weighted group. Tick marks indicate censored data. After overlap weighting analysis, PFS (P = .004) and OS (P = .010) were significantly longer in patients receiving chemo-anti–PD-1/PD-L1 than patients receiving anti–PD-1/PD-L1. chemo-anti–PD-1/PD-L1, combination of chemotherapy plus anti–PD-1/PD-L1 therapy; dMMR, mismatch repair-deficient; HR, hazard ratio; MSI, microsatellite instability; OS, overall survival; PFS, progression-free survival.