https://www.theregister.co.uk/2018/02/26/apple_icloud_on_google_servers/

If you chose the Apple ecosystem because you don't trust Google – bad news. Apple has confirmed for the first time that it now uses Google servers to store third-party data from iCloud users.

Apple has used Amazon Web Services and Microsoft's Azure to host iCloud data since 2011. Spreading the data to Google too shouldn't be news – and incredibly has been rumoured since 2007.