Provided is a novel treatment strategy for anti-PD-1 antibody treatment. A pharmaceutical composition including at least one substance selected from the group consisting of (i)-(iii) below, administered before, after, or simultaneously with administration of a PD-1 signal inhibitor. (i) ROS generators and substances that control downstream signals thereof, (ii) substances exhibiting an uncoupling effect and substances that control downstream signals thereof, and (iii) amino acids
