CD274 and granular cell tumor: However, in GCT, clinical studies of single immune checkpoint inhibition with PD-1/PD-L1 or CTLA-4 blockade has so far been of limited benefit with efficacy confined to GCT of an inflamed phenotype [14,15], such that more recently, combinations of checkpoint inhibitors, i.e., Nivolumab (anti-PD-1) and Ipilimumab (anti-CTLA-4), have come into focus.