Cemiplimab in AlloSCT/SOT Recipients With CSCC

* This an open-label, two cohort, phase I/II research study to evaluate the safety and effectiveness of Cemiplimab as a treatment for advanced cutaneous squamous cell carcinoma in participants who have received allogeneic hematopoietic stem cell or kidney transplants. * The research study procedures include screening for eligibility, study treatment, participant evaluations and safety follow-up visits. It is expected that about 12 people will take part in this research study. * Participants will be divided into two groups (cohorts) of allogeneic hematopoietic stem cell recipients or kidney transplants recipients. * Allogeneic hematopoietic stem cell recipients will only receive the study treatment drug of Cemiplimab. * Kidney transplant recipients will receive the study treatment drug of Cemiplimab along with the immunosuppressant drugs of Everolimus or Sirolimus and Prednisone to prevent kidney rejection. The U.S. Food and Drug Administration (FDA) has approved Cemiplimab as a treatment option for patients with advanced cutaneous squamous cell cancer, but the FDA has not approved the use of Cemiplimab in participants who have received allogeneic hematopoietic stem cell transplants or kidney transplants in the past. \-- Cemiplimab is a type of drug called a monoclonal antibody. Antibodies are proteins naturally found in your blood that fight infections. A monoclonal antibody is a special kind of antibody that is manufactured as a medication to target specific proteins in the body that may be involved this type of cancer. Cemiplimab is a human monoclonal anti-PD-1 antibody that works by blocking the programmed death-1 (PD-1), a cell receptor on immune cells that is involved in preventing immune cells from destroying other cells. Blocking the receptor is expected to help immune cells attack cancer cells.