Many jurisdictions require privacy policies that describe what personally identifiable information you collect. Under Europe's GDPR, as well as several US State laws, you need to get a visitor's consent before storing non-essential cookies on a user's browser.
Drupal CMS has a new "privacy" solution that uses a script called Klaro. This improves upon previous solutions by logging all cookies it sees that aren't already added to a policy, providing sophisticated grouping of cookies, and actually blocking them if a user does not provide consent. You can see this in action on this site -- you can control which cookies Freelock will store on your site, and if you visit one of our video pages without doing so, you'll see an overlay that allows you to accept just the cookies that YouTube requires to show you the video:
This product covers installing and configuring Klaro on a Drupal 10.3 or later site, and setting up policies for all cookies found. It also includes a followup check after the solution has been deployed for a week to add any cookies missed in the initial setup.
For WordPress, we substitute Klaro with a hosted Usercentrics plugin, which is included with a Termageddon License.