For e.g., even though TLS is end-to-end secure (and I don't doubt that), a website that uses CloudFlare front [1] is susecptible to its secure traffic being intercepted by CloudFlare, because by-design TLS would be terminated at CloudFlare servers'. However, note that the end-user does not notice that, rather he sees his traffic end-to-end encrypted.
[1] https://support.cloudflare.com/hc/en-us/articles/200170416-E...