Cutaneous squamous cell carcinoma (cSCC) is one of the most common cancers of the Caucasian population and accounts for 20% of all skin tumours. An S3 guideline of the German Guideline Program in Oncology has been available since 2019. The diagnosis is based on the clinical examination. Excision and histological confirmation is required for all clinically suspicious lesions to allow prognostic assessment and correct treatment. The therapy of first choice is complete excision with histological control of the surgical margin. In cSCC with risk factors such as tumor thickness >6 mm, sentinel lymph node biopsy may be discussed, but there is currently no clear evidence of its prognostic and therapeutic relevance. Adjuvant radiation therapy may be considered in cases of high risk of recurrence and should be tested in cases of inoperable tumors. The indication for electrochemotherapy should also be considered in the treatment of local or locoregional recurrence. The immune checkpoint inhibitor cemiplimab is approved for the treatment of inoperable or metastasized cSCC. In case of contraindications, chemotherapeutic agents, epidermal growth factor receptor (EGFR) inhibitors or palliative radiotherapy can be used. Since the evidence is low in these cases, a systemic therapy should be used preferentially within clinical studies. Follow-up care should be risk-adapted and includes a dermatological control, supplemented by ultrasound examinations in high-risk patients.