Method the present invention is provided to treat cancer (for example, B cell cancer, such as Hodgkin lymphoma or acute lymphoblastic leukemia), reduce its seriousness or inhibit growth.The method of the present invention includes the antibody or its antigen-binding fragment combined with programmed death 1 (PD 1) receptor-specific that therapeutically effective amount is applied to required individual, are combined with the bispecific antibody for being specifically bound to CD20 and CD3 of therapeutically effective amount.