Acquired resistance to immunotherapy by physical barriers with cancer cell–expressing collagens in non–small cell lung cancer

in tumor cells. COL3A1 formed a castle-like barrier for a cluster of tumor cells and prevented T cell infiltration, while COL6A1 formed an armor-like barrier surrounding individual tumor cells to protect them against direct T cell attack. Our data reveal a tumor cell-intrinsic mechanism of AIR, mediated by collagen-containing physical barriers, which immediately suggests a clinical treatment option.