PDCD1 and neoplasm: Lindrostat plus PD-1 blockade co-treatment did not enhance tumor control or increase survival, relative to outcomes in vehicle-treated mice (online supplementary figure S3E, F), reflecting outcomes reported for the ECHO-301 clinical trial using epacadostat to inhibit IDO activity.9 As expected, combined lindrostat and PD-1 blockade enhanced tumor control and prolonged survival after CDA treatment without dermal tumor relapse (online supplementary figure S3E, F).