Hi, I am a bit confused with these 2.
AWS SSO is used to give single-sign on capability to AWS accounts and business app within an AWS Organization. That means using SSO I can sign in to AWS MAnagement console and business application using the same credentials.
AWS AD service also can enable access to Management console and 3rd party application (if using Managed AD) for its AD member.
So what is actually the difference in those 2? If SSO is connected to Active Directory, essentially those 2 services both can enable SSO access to Management console and 3rd party application.