It provides a novel therapeutic strategy with inhibitors targeting PD-1/PD-L1. A pharmaceutical composition comprising a COX-2 inhibitor, which is administered either before, after, or simultaneously with the administration of an inhibitor targeting PD-1/PD-L1. An immunostimulatory effect enhancer for PD-1/PD-L1 targeting inhibitors, including COX-2 inhibitors.ＰＤ－１／ＰＤ－Ｌ１を標的とする阻害薬による新たな治療戦略を提供する。COX-2阻害薬を含み、PD-1/PD-L1を標的とする阻害薬を投与する前、後又は同時のいずれかの時期に投与する、医薬組成物。COX-2阻害薬を含む、PD-1/PD-L1を標的とする阻害薬の免疫賦活効果増強剤。
