Abstract With the aim to explore the interest of the thiosemicarbazide scaffold for the inhibition of the indoleamine 2, 3-dioxygenase (IDO), a promising therapeutic target for anticancer immunotherapy, a series of 32 phenylthiosemicarbazide derivatives was prepared and their IDO inhibition evaluated. Our study demonstrated that among these derivatives, compound 14 characterized with a 4-cyanophenyl group on the ...