Study of Afatinib in Advanced Cutaneous Squamous Cell Carcinoma

This trial is studying afatinib, a targeted oral medication, in people with advanced skin squamous cell carcinoma (a type of skin cancer) that cannot be removed by surgery or treated with radiation. **You may be eligible if...** - You are 18 or older - You have advanced or metastatic cutaneous squamous cell carcinoma (skin cancer that has spread or cannot be surgically removed) - You have already received immunotherapy (PD-1/PD-L1 drugs) unless you were not a candidate for it - You have at least one measurable tumor - Your blood counts, liver, and kidney function are within acceptable ranges **You may NOT be eligible if...** - You have not recovered from significant side effects of prior cancer treatments - You received another systemic treatment, major surgery, or radiation within the past 2 weeks - You are pregnant or unwilling to use contraception - You are unable to provide tumor biopsy samples before and during treatment Talk to your doctor to see if this trial is right for you.