The Fourth Industrial Revolution, driven by AI, is accelerating the growth of the digital economy, with cloud computing and networks serving as its core infrastructure. While cloud and AI provide computing power and intelligent capabilities, carrier networks play a critical role in delivering these capabilities to users efficiently and securely. As cloud services are deployed more rapidly and enterprises increasingly adopt multi-cloud environments, traditional carrier networks face growing challenges, including slow service provisioning, inflexible private-line connectivity, insufficient service isolation and SLA assurance, and a lack of unified coordination across cloud, network, and security. To address these challenges, carriers need to leverage intelligent networking technologies such as SDN to enable unified orchestration, automated configuration, and flexible resource allocation, achieving integrated cloud-network-security coordination and building a more agile, reliable, and scalable digital transport network for the cloud era.