Azure's service for creating private, high-speed connections between your on-premises networks and Microsoft's cloud. Like having a private tunnel that connects your office directly to Azure data centers.
A hospital uses ExpressRoute to securely connect their patient management systems to Azure while meeting strict healthcare compliance requirements.
All are private connectivity services that provide dedicated or partner-provisioned links from on-premises or colocation sites to the provider’s network, offering more consistent performance and often better security than the public internet. Differences are mainly in connectivity models (dedicated vs partner), available locations/partners, routing options (BGP), and pricing/egress structures.