Immune checkpoint inhibitor (ICI) represented by anti-programmed death 1 (PD-1) antibodies has made great progress in the treatment of solid tumors. Recently, ICI has been gradually used in hematological malignancies, and many clinical trials have shown that it could bring better therapeutic efficacies and significantly improve the prognosis of patients with hematological malignancies. This article reviews the research progress of ICI in hematological malignancies combined with the clinical studies from the 62nd American Society of Hematology (ASH) Annual Meeting.