MPR (≤10% viable tumor rest) was observed in 14/20 patients (70%), including 9 pCR (45%). At a median follow-up of 29 months, 15 patients (75%) were disease-free, including all patients with an MPR. Using gene expression analysis, PD-1 was significantly higher at baseline in responders vs nonresponders....Neoadjuvant atezolizumab plus chemotherapy leads to promising pathologic responses in G/GEJ cancer. Baseline PD-1 and neutrophil signature were associated with response.