This study will test a study drug called cemiplimab to see if it can help treat early-stage cutaneous squamous cell carcinoma (CSCC), a type of skin cancer. Cemiplimab works by helping the immune system to kill cancer cells. It binds to a protein called programmed cell death-1 (PD-1) on the surface of certain immune cells. The main purpose of this study is to compare how well cemiplimab works compared to surgery, when injected into the lesion. The study is looking at: * The side effects cemiplimab might cause * How well cemiplimab works