LP23, a non-arylmethylamine PD-1/PD-L1 inhibitor (IC 50: 16.7 nM), exhibits anti-tumor activity through the restoration of immune cell function in HepG2/Jurkat T cells and induction of HepG2 cell death. Additionally, LP23 demonstrates in vivo efficacy in the B16-F10 tumor model (TGI=88.6% at 30 mg/kg) [1].