The request-response cycle is the process of communication between a client and a server. The client sends a request to the server, which then processes the request and sends a response back to the client.
For example, when a user visits a website, their web browser sends a request to the server hosting the website. The server then processes the request and sends a response back to the web browser in the form of a web page. The web browser then displays the web page for the user to view.