I have a use case from Client.
They want to use the gateway as middleware between their authentication system and the Service provider.
In Simple terms
The client wants an API in the API Gateway which will authenticate the user from Microsoft AD which will be at the backend.
User hitting API Endpoint-->User gets a login form he/she fills it with username password-->The API gateway will redirect the Username and password to the Microsoft AD which is at the backend and will get a response if he/she are valid users-->Then after Successful response API Gateway needs to generate a Saml token by which user will be redirected to the Service at Salesforce.
I have seen Sample policies for the Gateway acting as an Identity Provider and Service Provider but in this case how can i build it, As i am very new to SAML and Salesforce.