سلام
اینها هر دو یکی هستند عزیز
Middleware خودش همون PipeLine
Middleware is software that's assembled into an app pipeline to handle requests and responses. Each component:
https://docs.microsoft.com/en-us/aspnet/core/fundamentals/middleware/?view=aspnetcore-3.1
مخصوص اعضای ویژه 
