Introduction Hematological malignancies are collectively the fourth most common of all cancers in the United States.1 Despite the major leaps forward in treatment options, relapsed and refractory disease remains a challenge. Progress for hematological malignancies has been exceptionally rapid due to improvements in treatment protocols, including the development of targeted therapies. For example, the multiple myeloma (MM) 5-year relative survival rate increased from 25% in the 1970s to 56% in 2012, and close to 75% in US-academic centers.1,2 However, it is estimated that every 9 minutes, someone in the US dies from a hematological malignancy.1 When chemotherapeutic options fail, novel immunologic approaches are needed