This study is being conducted to determine if belatacept is an appropriate alternative immunosuppressive medication (reducing the immune system's effect) when a kidney transplant patient develops new onset diabetes after transplant (NODAT). Patients who are diagnosed with NODAT will be approached with the opportunity to participate in this study. If they agree to participate, they will be randomized one-to-one (like a coin flip) to the study arm (belatacept) or the control arm (their current medication regimen). If a patient is randomized to the study arm, they will be tapered off of their current regimen when they have started receiving their monthly belatacept infusions. The control arm will mean the patient will continue their current, standard of care medications, but following the tacrolimus trough levels indicated within the study protocol. Different laboratory tests (i.e. fasting blood glucose) will be measured during the study to monitor the progression of NODAT in all patients.