Introduction: Cutaenous Adenosquamous carcinoma (ASC) is a rare, aggressive malignancy with complex clinical management. This presentation reviews the literature on ASC and presents the case of a 66-year-old female with metastatic ASC. Our patient developed multiple local recurrences despite wide excisions and adjuvant radiotherapy. Progression to unresectable locally advanced and metastatic disease was treated with cemiplimab with excellent response. This case presents the first described use of cemiplimab for metastatic ASC. The primary objectives are to review the nuance of ASC management, highlight the importance of histopathological diagnosis, and evaluate the potential of cemiplimab in treating metastatic or unresectable ASC. Methods: A retrospective chart review was conducted on a 66-year-old female diagnosed with ASC. Clinical and histopathological data, surgical treatments, radiotherapy, and imaging studies, were analysed. Additionally, a comprehensive review of existing literature was performed to identify management trends and outcomes for ASC. Treatment Recommendations: Surgical excision remains the primary treatment modality for ASC. Wide excision should be performed aiming for margins of 6-10mm. Moh's surgery can be considered. Radiation should be considered when perineural invasion is present or there is invasion beyond subcutaneous fat. Immune checkpoint inhibitors should be considered in metastatic or non resectable disease. Conclusion: Accurate diagnosis and tailored management are crucial for ASC due to high rates of local recurrence and potential for metastatic disease. The use of cemiplimab in this case demonstrates the potential for immune checkpoint inhibitors as an effective treatment for metastatic ASC.