FAP and neoplasm: To date, multiple approaches have been developed for tumor treatment by targeting FAP, such as anti-FAP antibodies (Welt et al., 1994; Hofheinz et al., 2003; Scott et al., 2003), vaccines (Lee et al., 2005; Loeffler et al., 2006), immunoconjugates (Ostermann et al., 2008), CAR-T cells, and FAP inhibitors (Wang et al., 2014; Lo et al., 2015; Teichgräber et al., 2015; Lindner et al., 2018).