IDO/TDO inhibitor

A compound represented by formula (I-2) or a pharmaceutically acceptable salt of the compound:

• wherein
• ring A represents an aromatic ring, a heterocyclic ring, or a condensed ring of two or more rings selected from an aromatic ring, and a heterocyclic ring, wherein ring A is selected from the group consisting of a benzene ring, a naphthalene ring, a quinoxaline ring, a thiophene ring, an indole ring, a benzothiophene ring, an imidazole ring, a quinoline ring, a quinazoline ring, and a pyridine ring;
• X is selected from the group consisting of a halogen atom, a substituted or unsubstituted linear or branched alkyl group, a substituted or unsubstituted linear or branched alkoxy group, a substituted or unsubstituted linear or branched alkenyl group, a substituted or unsubstituted linear or branched alkenyloxy group, a substituted or unsubstituted linear or branched alkynyl group, a substituted or unsubstituted linear or branched alkynyloxy group, a substituted or unsubstituted cycloalkyl group, a substituted or unsubstituted cycloalkenyl group, an alkyl halide group, an alkyloxy halide group, a cyano group, and when m is 2 to 6, each X is the same or different;
• m represents an integer of 0 to 6;
• Z is selected from the group consisting of O, S, SO, SO2, and Se,
• s represents an integer of 1 to 8,
• R6 is selected from the group consisting of a substituted or unsubstituted aryl group, a substituted or unsubstituted cycloalkyl group, and a substituted or unsubstituted heterocyclic group.