23. Women of childbearing potential not willing to use adequate contraception, defined as hormonal birth control or intrauterine device, during the trial and for 1 year after the last dose of daratumumab or nivolumab or lenalidomide. Men who are sexually active with women of childbearing potential who are not willing to use adequate contraception for the duration of treatment with the study drugs and for 1 year after the last dose of daratumumab or nivolumab or lenalidomide.