A short summary (2-3 sentences) at the top can help, especially if you’re changing fields or your experience isn’t self-explanatory from your work history alone. It should say who you are, what you’re looking for, and one or two things that make you a strong candidate — not a generic sentence like “hardworking team player seeking opportunities.”
If your CV is already clear and well-organized, a summary is optional, not mandatory. Don’t add one just to fill space.
Quick answer: Optional, but useful if your background needs context. Keep it to 2-3 specific sentences, not generic filler.