Advanced cSCC in kidney transplant recipient – seeking advice

Hello.
My family member is a 44-year-old kidney transplant recipient with aggressive cutaneous squamous cell carcinoma.

He had left axillary nodal involvement treated with surgery, but during radiotherapy he developed rapid local progression in the left chest wall. His doctors are considering cemiplimab, but there is major concern about kidney graft rejection.

We are looking for:
1. Patients or caregivers with similar experience (advanced cutaneous SCC in a transplant recipient)
2. Centers with strong experience in this setting
3. Information about clinical trials for transplant recipients with advanced cutaneous SCC

We are not looking for alternative therapies, only for reputable centers, trials, and real patient experiences.

We are based in Spain but we can travel.

We really appreciate any guidance.