The fact that PD‐L1 expression in MPN cells correlates with the JAK2‐V617F mutational burden and that among JAK2‐V617F positive patients, those with homozygous JAK2‐V617F mutation display higher PD‐L1 expression, indicate that the mutant JAK2 dosage and subsequent activation of the JAK–STAT pathway, lead to PD‐L1 upregulation, which is in line with the results published by Prestipino et al.14 The gene discussed is JAK2; the disease is myeloproliferative neoplasm.