Because CAR T-cell therapy has been FDA-approved for the treatment of R/R MM, and multiple reports indicated that high level expression of IMs like PD1, LAG3, and TIM3 and their receptors were associated with T-cell exhaustion and poor response to CAR-T therapy in acute lymphoblastic leukemia (41, 42), probably R/R MM with immune-low status is more recommend to receive CAR-T therapy. Here, HAVCR2 is linked to acute lymphoblastic leukemia.