In what situations would it be necessary or beneficial to access cookies from other domains using PHP?

When working with cross-origin requests or integrating third-party services, it may be necessary to access cookies from other domains using PHP. This can be beneficial for authentication, tracking user behavior across different domains, or sharing session information between multiple websites.

// Set the domain parameter to allow access to cookies from other domains
ini_set('session.cookie_domain', '.example.com');

// Access the cookie from another domain
$cookieValue = $_COOKIE['cookieName'];