Content delivery networks (CDNs) significantly impact mobile content delivery by enhancing speed, reliability, and security. CDNs use edge servers to reduce latency and load times by up to 50%, optimize content for mobile devices through compression and lazy loading, ensure 99.9% uptime via load balancing and failover, and offer DDoS protection and encrypted data transmission. They also cut bandwidth costs and reduce the need for regional data centers. Challenges include cache invalidation, device/network variability, and compliance with geo-blocking laws. With 5G, CDNs will further evolve to support low-latency applications like AR/VR and IoT.