Apple was once considering a service to allow their iCloud users to encrypt their data. In 2017, Apple canceled their plans to roll that out. According to the New York Post, Apple’s legal team killed the idea shortly after a shooting in San Bernardino California.
That same report states that the FBI complained that allowing iPhone users to encrypt their iCloud backups would cause issue for law enforcement to gather evidence against iPhone using suspects.
Apple has since switch from end-to-end encryption to just encrypting super-sensitive information on iCloud backups. President Trump was also vocal on Apple not helping law enforcement in their investigation into the San Bernardino shooting,