Immune checkpoint inhibitors targeting programmed cell death protein- 1 (PD- 1 ) or programmed death ligand-1 (PD-L1) have shown certain efficacy in some clinical studies for refractory and recurrent children's malignant blood diseases and tumors. It has certain anti-tumor effect on refractory and recurrent Hodgkin lymphoma and primary mediastinal B-cell lymphoma, and is relatively well tolerated in children and adolescents. PD-1/PD-L1 inhibitors do not seem to increase the infection rate, but for glucocorticoid and/or TNF supplementation-伪 targeted drug immunosuppressive therapy suggests the use of preventive measures against Pneumocystis carinii. The combination of PD- 1 /PD-L 1 inhibitors with other types of immune checkpoint inhibitors, chemotherapy agents and histone deacetylase inhibitors is still in the clinical research stage. The dosage, course of treatment and scheme of PD- 1 /PD-L 1 inhibitors for children still need further research in multiple centers. Whether they can achieve lasting antitumor effect also needs further research.