Cemiplimab in AlloSCT/SOT Recipients With CSCC

Inclusion Criteria: * Patients must have histologically confirmed, advanced or metastatic cutaneous squamous cell carcinoma (cSCC) with 1 or more measurable lesions (greater than or equal to 1 cm). * A history of either (Cohort 1) allogeneic hematopoietic stem cell transplant (alloHSCT) and ≥ 2 years or 730 days from day 0 of their HSCT with adequate bone marrow function (see Section 3.1.6) and off of all systemic immunosuppression (topical agents permitted) for at least 3 months prior to enrollment; sequelae of chronic graft versus host disease (GVHD) is permitted (i.e. chronic dry eyes, sclerodermatous skin changes, etc.) if the patient is not on systemic immunosuppression, or (Cohort 2) a renal transplant with a functioning allograft (at least 6 months from allograft transplant) as determined by estimated glomerular filtration (GFR) rate (CKD-EPI equation \[40\], Appendix A) ≥30 mL/min, baseline proteinuria lower than 0.5 g/day (spot urine protein-creatinine ratio), and off antiproliferative immunosuppressive medications. * Age 18 years or older. * Eastern Cooperative Oncology Group (ECOG) performance status ≤ 2 (Karnofsky ≥ 60%, see Appendix B). * Participants must have adequate organ and marrow function as defined below: * leukocytes ≥ 2,200/mcL * absolute neutrophil count ≥ 1,000/mcL * platelets ≥ 90,000/mcL * total bilirubin within normal institutional limits (except in cases where Gilbert syndrome is known or suspected, where total bilirubin should be \< 3 m…