Our research group previously developed a PD-L1 blocking peptide, OPBP-1, with the sequence of Gqsehhmrvysf-NH2 (lower-case letters represent D-amino acids) and proved its excellent anti-tumor efficacy; thus, it was selected as a model peptide drug and encapsulated in the internal aqueous phase of a double emulsion [17]. The gene discussed is CD274; the disease is neoplasm.