Preface: Netlify is a platform that enables static development, while Netlify CMS is an open source project created by Netlify.
In a broad sense there's nothing that can't work with the CMS - you can integrate a Mailchimp sign up form in your template and never have the CMS touch it. Beyond that, reach out in the spectrum community for help with a specific use case: https://spectrum.chat/netlify-cms
In a broad sense there's nothing that can't work with the CMS - you can integrate a Mailchimp sign up form in your template and never have the CMS touch it. Beyond that, reach out in the spectrum community for help with a specific use case: https://spectrum.chat/netlify-cms