A Content Delivery Network (CDN) improves website performance by distributing content across multiple servers located in various geographical areas. When a user requests a webpage, the CDN delivers the content from the nearest server, resulting in faster loading times and a better user experience. CDNs also help in managing traffic spikes, improving website reliability, and enhancing security by providing DDoS protection and secure content delivery. This ensures websites can handle large volumes of visitors without compromising performance.