The present disclosure describes combination therapies comprising an antagonist of Programmed Death 1 receptor (PD-1) and a multi-RTK inhibitor, and the use of the combination therapies for the treatment of cancer. The multi-RTK inhibitor may be represented by Formula (I): wherein R1 is C1-6 alkyl or C3-8 cycloalkyl, R2 is a hydrogen atom or C1-6 alkoxy, and R3 is a hydrogen atom or a halogen atom. A tumor therapeutic agent is disclosed that combines a compound or pharmaceutically acceptable salt thereof represented by Formula I and an anti-PD-1 antibody.