BMS-1166-N-piperidine-CO-N-piperazine is a chemical compound that contains a PD-1/PD-L1 immune checkpoint ligand and a PROTAC linker. It can be utilized in the synthesis of PROTAC PD-1/PD-L1 degrader-1, which effectively inhibits the PD-1/PD-L1 interaction, demonstrating an IC50 value of 39.2 nM.