FGL1 and neoplasm: In addition to MHC-II, LAG-3 also interacts with other ligands, such as fibrinogen-like protein 1 (FGL1), which inhibits the activity of antigen-specific T cells [352,353]; galectin-3 (Gal-3) [354], involved in T cell anergy in the TME; LSECtin, which affects tumor growth [355]; and the TCR-CD3 complex, which regulates the immune synapse [356].