Phase I/II Study of Perioperative Chemotherapy Plus Immunotherapy Followed by Surgery in Localized Esophageal and Gastroesophageal Adenocarcinoma

Inclusion Criteria (cohort 1 and cohort 2) * Signed Informed Consent Form * Age ≥ 18 years at time of signing Informed Consent Form * Ability to comply with the study protocol, in the investigator's judgment * Histologically or cytologically confirmed esophageal or gastroesophageal type I or II adenocarcinoma * No prior therapy including chemotherapy or radiation therapy. * Patients with T1N1, and T2-3 with any N will be eligible. * ECOG Performance Status of 0-1 * Adequate hematologic and end-organ function, defined by the following laboratory test results, obtained within 14 days prior to initiation of study treatment: * ANC ≥ 1.5 x 109/L (1500/L) without granulocyte colony-stimulating factor support * Lymphocyte count ≥ 0.5 x 109/L (500/L) * Platelet count ≥ 100 x 109/L (100,000/L) without transfusion * Hemoglobin ≥ 90 g/L (9 g/dL) Patients may be transfused to meet this criterion. * AST, ALT, and alkaline phosphatase (ALP) ≤ 2.5 x upper limit of normal (ULN) * Serum bilirubin ≤ 1.5 x ULN with the following exception: Patients with known Gilbert disease: serum bilirubin level ≤ 3 x ULN * Serum creatinine ≤ 1.5 x ULN \[or\] Creatinine clearance ≥ 70 mL/min (calculated using the Cockcroft-Gault formula)} * Serum albumin ≥ 25 g/L (2.5 g/dL) * For patients not receiving therapeutic anticoagulation: INR and aPTT ≤ 1.5 x ULN * For patients receiving therapeutic anticoagulation: stable anticoagulant regimen * Medically fit for surgery based on surgeon's asses…