The goal of this multidisciplinary project is to advance in biomaterials and medical technology that allow greater control over how CAR-T cells and immunostimulatory cytokines are delivered. This may lead to the development of personalized cell therapies to treat solid tumors. By including CAR-T cells and the cytokine IL-2 in advanced hydrogels, a more localized and prolonged release of these components can be achieved, reducing side effects. In addition, the Microfluidics group of the UPV/EHU develops microfluidic devices that can help evaluate and optimize these therapies by allowing the creation of in vitro models of cell co-cultures with a controlled microenvironment and monitoring their evolution with high precision in the space and time. The project focuses on the development of CAR-T to treat triple negative breast cancer, which is the most aggressive and difficult to treat type. Currently, there is only one accepted immunotherapy for this type of tumor in advanced stages, which is the use of anti-PD-L1 antibodies. This project is innovative in the treatment of breast cancer as it focuses on developing new therapies for a type of cancer that currently lacks effective options.