Two ongoing interventional trials, ‘DART: Dual Anti-CTLA-4 and Anti-PD-1 Blockade in Rare Tumors’ of the National Cancer Institute (NCI) and ‘Phase II Trial of Nivolumab Plus Ipilimumab in Patients With Aggressive Pituitary Tumors’ of the Memorial Sloan Kettering Cancer Center, USA, may provide further evidence for this hypothesis. Here, PDCD1 is linked to pituitary tumor.