To take advantage of favorable pharmacokinetics and tumor penetration compared to a full monoclonal antibody (mAb), a nanobody targeting LAG-3 was developed to specifically target and allow quantification of LAG-3 expression on tumor-infiltrating lymphocytes (TILs) in different mouse cancer models treated with anti-PD-1 mAbs [49]. This evidence concerns the gene LAG3 and neoplasm.