Overview of Platform changes
In the past version of ASP.Net, Web forms and MVC used to share the underlying infrastructure. In .Net core these platforms are unified into one MVC. The Webforms is not part of ASP.NET core anymore.

The prior versions of ASP.NET MVC used to provide an underlying application life cycle events based on HTTP modules & handlers and IIS hosting and application level events . Http Events and Handlers are not existing in ASP.NET Core.

Most of the events and functionality are provided in ASP.Net core by middleware.

What is life cycle
A Series of components, events or stages of an application that processes a request or respond to user interaction. In MVC the request life cycle refers to all of the components and stages that interact to process an HTTP request.

Following diagram shows an overview of ASP.Net core MVC application.

Asp.Net Core MVC Life cycle overview

Read More