A humanized monoclonal antibody directed against the transforming growth factor beta (TGFbeta) activator, glycoprotein A repetitions predominant (GARP; leucine-rich repeat-containing protein 32; LRRC32), with potential immunomodulating and antineoplastic activities. Upon administration, livmoniplimab selectively targets and binds to GARP which interferes with the production and release of active TGFbeta by regulatory T-cells (Tregs). Selective inhibition of the release of TGFbeta from Tregs leads to a reversal of immunosuppression thereby increasing the immune response to tumor cells. GARP, a leucine-rich repeat-containing protein, is essential for the expression of TGFbeta on the cell surface of activated Tregs; it plays an important role in regulation of the immune cell function.