You need an ETA for Cape Verde if you have a Guinean passport
Visa options for Cape Verde
Electronic travel authorization
Travelers need travel authorization to visit Cape Verde for Business or Tourism. The Electronic Travel Authorization (EASE) for Cape Verde is required for visa-exempt visitors entering Cape Verde. It is an online application. If approved, travelers will receive an eTA confirmation electronically. When travelers arrive in Cape Verde, the border crossing will ask for a passport and check electronic records to ensure travelers have the proper visa. Note: The traveler's eTA is electronically linked to the passport and valid for up to 1 year. When travelers receive a new passport, they must apply for a new eTA. For all other visas, please visit the government site. Travelers must complete the EASE application online a minimum of 5 days before traveling to Cape Verde.