A novel therapeutic strategy for the anti-PD-1 antibody therapy is provided. A pharmaceutical composition which comprises at least one substance selected from the group consisting of the following (i) to (iii) and is administered before, after or simultaneously with the administration of a PD-1 signal inhibitor: (i) ROS generators and substances that regulate downstream signaling pathways thereof, (ii) substances exhibiting an uncoupling effect and substances that regulate downstream signaling pathways thereof, and (iii) amino acids.
