Besides targeting the PD-1/PD-L1 axis in MPN, another clinical trial (phase I/Ib) aims to study the side effects, toxicity and best dose of the CTL-A4 inhibitor Ipilimumab or the PD-1 inhibitor Nivolumab in patients with hematologic malignancies. The gene discussed is PDCD1; the disease is myeloproliferative disorder.