Microsoft Azure Stack (MAS) was announced by Microsoft at May 4th 2015,

Microsoft Azure Stack is a set of products that extend Azure services to your own data center. It allows you to run Azure services on-premises, giving you the flexibility to run applications in a consistent hybrid cloud environment. Essentially, it can behave like a mini version of Azure that you control.
There are however, as you always have with Microsoft products, different Azure Stack Configurations.
Azure Stack Edge
A physical device (appliance) that brings Azure’s compute, storage, and intelligence capabilities to the edge of your network. It’s designed for remote locations where connectivity to the main cloud might be intermittent or where data needs to be processed locally.
Use Cases: Data preprocessing for AI/ML workloads, Internet of Things (IoT) solutions, data collection and processing at remote sites like factories or retail stores.
Key Features: Local data processing, AI/ML inferencing at the edge, integration with Azure cloud for further analysis and storage.
Azure Stack HCI (Hyper-Converged Infrastructure)
A solution for running virtualized workloads on-premises using a hyper-converged infrastructure. It combines compute, storage, and networking into a single system and is optimized for running virtual machines (VMs) and modern applications.
Use Cases: Data center modernization, running virtual desktops, consolidating servers, and hosting enterprise applications.
Key Features: High performance and scalability, integrated with Azure services for backup, monitoring, and disaster recovery.
Azure Stack Hub
A full-fledged hybrid cloud platform that extends Azure services to your data center. It provides a consistent development and operations experience with the same APIs, tools, and services available in the Azure public cloud.
Use Cases: Developing and running cloud applications in on-premises environments, regulatory compliance where data residency is critical, disconnected or intermittently connected environments.
Key Features: Full Azure IaaS and PaaS services on-premises, consistent application development and deployment, integrated with Azure for hybrid cloud scenarios.
Knowing all this, when you compare these installations to a traditional on-premises server setup that provides basic infrastructure services like file storage, application hosting, and directory services, you can easily spot the key differences.
In short, Azure Stack Edge is ideal for edge computing and local data processing. Azure Stack HCI is meant for modernizing data centers and running virtualized workloads. Azure Stack Hub is for you when you want to extend full Azure services to on-premises environments for hybrid cloud solutions. Of course we still have a use for Windows Server, which is our go-to platform to run business applications and services.
Each Azure Stack configuration serves different needs and scenarios, providing flexibility and powerful capabilities beyond what a typical Windows Server installation can offer.