Google holds more extensive data on Android users than some ever realize. That data can be used by the company to sell targeted advertising and to track into stores those consumers who saw ads on their phone or computer urging them to visit. This also means governments and courts can request the detailed data on an individual’s whereabouts.
An article by David Yanofsky in the Quartz web site describes the problems. You can find the article at: http://bit.ly/2n92eP9.
If you don’t want to be tracked, switching to an iPhone will not solve your problem. Apple also tracks users although perhaps not as much as Google does. However, I have written in the past about cell phones that are much more secure than the iPhones or the normal Android phones. See my past articles at:
In addition, this article is not about cell phones exactly, but it describes a new, secure cellular network: https://privacyblog.com/2017/12/02/volunteers-around-the-world-build-surveillance-free-cellular-network-called-sopranica/