FAP and malignant pleural mesothelioma: Fibroblast activation protein (FAP), a transmembrane serine protease/type 2 dipeptidyl peptidase, has been shown to be one of the preponderantly expressed surface markers of most CAF populations and correlates with poor clinical outcome in various carcinomas [90, 91]. With this rationale, anti-FAP CAR-T cells were developed to target CAFs, with multiple concepts aiming to treat malignant pleural mesothelioma (MPM) in human and murine models [92, 93].