How can different domains or subdomains impact PHP session continuity?

When PHP sessions are used across different domains or subdomains, the session cookie may not be accessible due to the SameSite attribute restrictions. To ensure session continuity, the session cookie's SameSite attribute should be set to "None" and the "Secure" attribute should be set if using HTTPS.

// Set session cookie attributes for cross-domain continuity
ini_set('session.cookie_samesite', 'None');
ini_set('session.cookie_secure', true);