• Gender is not limited, age 18-75 years old (including the threshold value);

• The expression of CD123 in tumor cells was detected by flow cytometry.

• Patients with relapsed/refractory AML or BPDCN diagnosed with CD123 positive: 1) AML: a. Recurrent: After complete response (CR), the recurrence of leukemia cells in peripheral blood or bone marrow original cells ≥5% (except for other reasons such as bone marrow regeneration after consolidation chemotherapy) or the occurrence of extramedullary leukemia cell infiltration; b. Refractory: refers to those who have failed to receive 2 courses of treatment with standard protocols; Patients recurrence within 12 months after CR with consolidation and intensive treatment; Recurrence after 12 months but failed to respond to conventional chemotherapy; 2 or more relapses; Extramedullary leukemia persists;

⁃ 2\) BPDCN: has failed to receive guidelines-recommended salvage therapy or is unable to tolerate current therapy, and has persistent or recurrent disease in any of the peripheral blood, bone marrow, lymph nodes, spleen, skin lesions, or other site lesions.

⁃ 4\. Expected survival time is more than 12 weeks;

⁃ 5\. ECOG 0-2 points (Appendix 2);

⁃ 6\. No serious mental disorders; The functions of important organs are basically normal:

• Cardiac function: echocardiography indicated cardiac ejection fraction ≥50%, and no obvious abnormality was found in electrocardiogram;

• Renal function: serum creatinine ≤2.0×ULN;

• Liver function: ALT and AST ≤ 3.0×ULN;

• Total bilirubin and alkaline phosphatase ≤ 2.0×ULN (Gilbert syndrome ≤ 3.0×ULN);

• Blood oxygen saturation \> 92%.

• 7\. The patient or his/her guardian agrees to participate in the clinical trial and signs the ICF, indicating that he/she understands the purpose and procedure of the clinical trial and is willing to participate in the study.