Integrating Chat using PubSub in an iOS Video Call App enhances user communication and experience by enabling real-time messaging during video calls. This integration adds a layer of interactivity, allowing users to chat, share information, and collaborate seamlessly while engaging in video conversations. By incorporating PubSub technology, the app ensures reliable message delivery and synchronization across all connected devices, enhancing the overall user experience. Key benefits include real-time communication, seamless collaboration, enhanced user experience, reliable message delivery, and scalability.