To obtain a carrier-free co-assembled system, the "one-bead-one-compound (OBOC)" combinatorial chemistry approach was used to construct a PD-L1-targeting peptide library with a diversity of 10 6 . The OBOC peptide library with a NH2-EX10X9X8X7X6X5X4X3X2X1-COOH motif was designed and synthesized. In this library, the X1X3X5X7X9 position were diversified with hydrophilic and electric residues including T, D, K, H, E, S, N and Q. The X2X4X6X8X10 position were diversified with hydrophobic residues including F, Y, W, I, V, A and Y. Through our previous screening protocols And the value also demonstrated higher binding ability than the intrinsic receptor PD-1 . Next, molecular docking simulations were performed between EH and PD-L1 protein to predict the detail binding sites. As shown in Fig. , the intermolecular forces between EH and PD-L1 protein were dominated by π-π interaction and hydrogen bonds.