Whenever a request arrives into your application, you need to determine the tenant that the request is intended for. When you have tenant-specific infrastructure that may even be hosted in different geographic regions, you need to match the incoming request to a tenant. Then, you must forward the request to the physical infrastructure that hosts that tenant's resources, as illustrated below:
https://learn.microsoft.com/en-us/azure/architecture/guide/multitenant/considerations/map-requests
