A Study of Metastatic Gastrointestinal Cancers Treated With Tumor Infiltrating Lymphocytes in Which the Gene Encoding the Intracellular Immune Checkpoint CISH Is Inhibited Using CRISPR Genetic Engineering

Inclusion Criteria: * Diagnosis of metastatic gastrointestinal epithelial cancer with progressive disease following at least one first line standard therapy. When available, archived tissue from original diagnosis will be obtained for research related testing. * Must have measurable disease per RECIST 1.1 with at least one lesion identified as resectable for TIL generation (minimum volume of tumor tissue required is 1 cm\^2 as single mass or fragments) and at least one other lesion meeting the RECIST criteria for measurable to serve as an indicator of disease response. The location of the tumor for TIL generation and method used to obtain (i.e. laparoscopy, endoscopic ultra sound, etc.) will be determined based on an individual patient's disease. * Patients with 3 or fewer brain metastases that are less than 1 cm in diameter and asymptomatic are eligible. Lesions that have been treated with stereotactic radiosurgery must be clinically stable for 1 month after treatment for the patient to be eligible. Patients with surgically resected brain metastases are eligible. Patients must not be receiving systemic steroids. * Brain metastases are assessed using the Response Assessment in Neuro-Oncology Brain Metastases (RANO-BM) criteria. * Age ≥ 18 years and ≤ 70 years. * Clinical performance status of ECOG 0 or 1. * Serology testing within 3 months of study enrollment (tumor collection): * Seronegative for HIV antibody. (The investigational treatment being evaluated in this protoc…