Nivolumab +/- Relatlimab Prior to Chemoradiation With II/III Gastro/Esophageal Cancer

Inclusion Criteria: * Men and women aged ≥ 18 years old * Histologically proven (squamous cell or adenocarcinoma) esophageal or gastro- esophageal junction cancer (core biopsy required). * Stage II/III disease as per AJCC staging 7.0 * Baseline imaging with FDG-PET scan and endoscopic ultrasound within 28 days prior to registration * ECOG performance status 0-1 (see Appendix B). * Adequate oral intake/nutritional status without the need for enteral or parenteral feeding during chemoradiation or preoperative period * Adequate organ function as follows: * Leukocytes ≥ 2,000/mm3 * Absolute neutrophil count (ANC) ≥ 1000/mm3 * Platelet count ≥ 100,000/mm3 * Hemoglobin ≥ 9 g/dL * Creatinine ≤ 2.0 mg/dL * Bilirubin (total) within normal institutional limits (except subjects with Gilbert Syndrome who must have total bilirubin \< 3.0 mg/dL) * AST(SGOT), ALT(SGPT), and alkaline phosphatase ≤ 2.5 times the upper limit of normal * PT such that international normalized ratio (INR) is ≤ 1.5 (or an in-range INR, usually between 2 and 3, if a patient is on a stable dose of therapeutic warfarin and a PTT ≤ upper limit of normal * Adequate cardiac function as defined by: no evidence of PR prolongation or AV block on baseline electrocardiogram (ECG). * Radiation oncology consultation within 28 days to confirm that disease can be encompassed in the radiotherapy field and that normal tissue constraints can be met. * Subjects must have adequate lung function to permit surgical re…