Biotherapy Center of the First Affiliated Hospital, Zhengzhou University, Zhengzhou 450052, China and Department of Medicine, Cancer Therapy & Research Center, University of Texas Health Science Center, San Antonio, TX 78229, USA and Robert H Lurie Comprehensive Cancer Center, Department of Medicine – Division of Hematology/Oncology, Northwestern University, Feinberg School of Medicine, 300 E Superior Street‐Tarry 13‐766, Chicago, IL 60611, USA Tel.: +1 312 503 1104 Fax: +1 312 503 0189 bin.zhang@northwestern.edu Opportunities and challenges for anti-CD73 cancer therapy