 This study will evaluate the ability of Expanded Natural Killer ENK cells to treat multiple myeloma when administered as part of a regimen consisting of Elotuzumab and a stem cell transplant. Natural killer cells are a special type of white blood cells that are already present in the body which have the ability to kill myeloma cells. In this study, natural killer cells will be collected and then treated in a laboratory to activate and expand the number of cells to increase the dose and the anti-myeloma activity of the cells before they are transfused back into the subject. Elotuzumab is a protein drug approved by the United States Food and Drug Administration FDA for patients with previously treated multiple myeloma and works by activating natural killer cells already present in the body and targeting a protein called SLAMF7 which is present on both natural killer cells and myeloma cells. The investigators hope that administering Elotuzumab in combination with ENK cells will enhance the anti-myeloma activity of the ENK cells. 