This is a 12-month, randomized study that involves pre-transplant procedures, a kidney transplant, and post-transplant procedures. After kidney transplantation, every patient, whether in a research study or not, must take immunosuppressive medications to prevent their immune system from rejecting their new kidney. A rejection can harm your new kidney which can lead to lower kidney function. The purpose of this research is to test the safety and effectiveness of siplizumab for kidney transplant patients. Study participants who receive the new study treatment will be compared to participants receiving the most common approved immunosuppressive treatments referred to as "standard of care". You will be randomized into either the study group or the "standard of care" group, like flipping a coin. Because this is a research study, siplizumab will only be given to you during the research study as in infusion treatment. Siplizumab is an investigational medication, which means it has not been approved by the Food and Drug Administration (FDA) and is currently not "on the market" in any country. The potential risks of siplizumab are infusion reactions, inflammatory reactions, immunosuppression, and infections. The benefits of the study treatment are unknown but are suspected to decrease chances of rejection and increase the chance of effective kidney function. An alternative to this study would be to not participate and pursue the standard of care treatment after your kidney transplant.