In this work, using a variety of in vitro models, including patient-derived tumor organoids (PDTOs) we demonstrate that oxaliplatin-based chemotherapy reshapes the TME via an increase in ROS-mediated MondoA-dependent TXNIP expression, resulting in decreased expression and secretion of GDF15, leading to a decrease in regulatory T-cell (Treg) differentiation and increase in CD8 T-cell activity. This evidence concerns the gene GDF15 and neoplasm.