The objectives of the study are:

• To describe the effectiveness of cemiplimab 350 mg administered every 3 weeks (Q3W) for treatment of patients with advanced (defined as locally advanced or metastatic [nodal or distant]) cutaneous squamous cell carcinoma (CSCC) and patients with advanced (defined as locally advanced or metastatic [nodal or distant]) basal cell carcinoma (BCC) in real-world clinical settings
• To evaluate the safety of cemiplimab based on incidence of treatment related immune-related adverse events (irAEs), infusion related reactions (IRRs), and treatment related serious adverse reactions (TSARs) in patients with advanced CSCC and patients with advanced BCC receiving cemiplimab treatment in real world clinical settings
• To describe patient experience, including patient reported quality of life (QOL) and functional status, and clinician reported performance status in a real-world setting for patients with advanced CSCC and patients with advanced BCC
• To describe baseline characteristics that could potentially be associated with health-related outcomes for patients with advanced CSCC and patients with advanced BCC undergoing treatment with cemiplimab
• To describe patients who receive cemiplimab as treatment for CSCC or BCC in a real-world setting
• To describe real-world use patterns of cemiplimab for CSCC and BCC
• To investigate the long-term effects and effectiveness of cemiplimab in patients with advanced CSCC or advanced BCC
• To describe the effectiveness of cemiplimab in immunosuppressed and immunocompetent patients with advanced CSCC or advanced BCC, regardless of etiology, per available data
• To describe the effectiveness of cemiplimab after prior exposure to radiation therapy for CSCC per available data
• To describe the effectiveness of cemiplimab as a first-line (1L) or later systemic treatment in patients with advanced CSCC, regardless of etiology, per available data
• To describe the effectiveness of cemiplimab in patients with advanced BCC based on treatment patterns (reason for discontinuation, treatment exposure, etc) of prior Hedgehog inhibitor (HHI) usage

Key Inclusion Criteria:

• Eligible for treatment with and prescribed cemiplimab for advanced CSCC or advanced BCC in accordance with approved prescribing information as described in the protocol

Key Exclusion Criteria:

• Receiving cemiplimab for an indication other than advanced CSCC or advanced BCC
• Any condition that, in the opinion of the investigator, may interfere with patient's ability to participate in the study
• Patients concurrently participating in any study including administration of any investigational drug (including cemiplimab) or procedure (including survival follow up)

Note: Other protocol defined Inclusion/Exclusion Criteria apply

Patients in this study will include men and women ≥18 years of age who have recently initiated, or who plan to initiate treatment with commercially available cemiplimab for laCSCC/mCSCC or laBCC/mBCC in a real-world setting.

All Individual Patient Data (IPD) that underlie publicly available results will be considered for sharing.

When Regeneron has:

• received marketing authorization from major health authorities (e.g., FDA, European Medicines Agency (EMA), Pharmaceuticals and Medical Devices Agency (PMDA), etc.) for the product and indication or has globally discontinued development of the product for all indications on or after April 2020 and has no plans for future development
• made the study results publicly available (e.g., scientific publication, scientific conference, clinical trial registry)
• the legal authority to share the data, and
• ensured the ability to protect participant privacy

Qualified researchers can submit a proposal for access to individual patient or aggregate level data from a Regeneron-sponsored clinical trial through Vivli. Regeneron's Independent Research Request Evaluation Criteria can be found at: https://www.regeneron.com/sites/default/files/Regeneron-External-Data-Sharing-Policy-and-Independent-Research-Request-Evaluation-Criteria.pdf