Nivolumab infusion (Per Section 5.12.1) 9. Vital Signs (including ambulatory O2 sat) per Section 11 5.11 Follow Up Participants will be followed monthly for the first 6 months following their last dose of treatment. Participants who complete treatment per protocol will be followed as outlined in section 5.11.1 and then followed for Progression Free Survival as outlined in section 5.11.2. Participants taken off treatment due to toxicity will be followed as outlined in section 5.11.1 and will continue to be followed for Progression Free Survival as outlined in section 5.11.2. Participants taken off treatment due to disease progression or to start alternative anti-myeloma therapy per MD discretion will be required to do a toxicity assessment visit 30 days after the last dose of study treatment. Participants then will continue to be followed for Survival for 5 years. Requirements for the toxicity assessment visit are outlined in section 5.11.3. 5.11.1 Active Follow Up (+/- 7 days) Participants will be followed monthly for 6 months following the last dose of treatment on study. 1.