An object of the present invention is to provide a medicine obtained by combining a liposome composition containing a drug in a liposome and an immune checkpoint inhibitor. According to the present invention, there is provided a medicine in which (A) a liposome composition and (B) an immune checkpoint inhibitor are administered simultaneously or sequentially. The (A) liposome composition comprises a hydrophilic polymer modified Diacylphosphatidylethanolamine (diacylphos phatidylethanolamine), dihydrosphingomyelin, and cholesterol are liposome compositions that constitute liposome membranes. The liposome composition contains a drug, and the inner aqueous phase contains ammonium sulfate The molar ratio of the phase sulfate ion to the total aqueous phase drug is 0.36 or more.本發明的課題為提供一種將脂質體內含藥物之脂質體組成物及免疫檢查點抑制劑組合而得到之醫藥。依本發明，提供一種將(A)脂質體組成物及(B)免疫檢查點抑制劑組合而同時或依次投予之醫藥，該(A)脂質體組成物係包含經親水性高分子修飾之二醯基磷脂醯乙醇胺(diacylphos phatidylethanolamine)、二氫鞘磷脂及膽固醇類作為脂質體膜的構成成分之脂質體組成物，其中前述脂質體組成物內含藥物，內水相包含硫酸銨，內水相硫酸離子相對於總水相藥物的莫耳比為0.36以上。
