Android and Malware: Using an open platform like Android means you have to be willing to take the risk of the bad along with the good. Without getting into a pro-and-con debate between Android and iOS, it is a fact that Android hosts more malware than the iOS platform, and this is due, in part, to its open ecosystem.
So Google engineers are constantly trying to discover ways to detect malware that is uploaded to the Google Play Store and lies in wait for unsuspecting users. 
A recent Digital Trends article describes how this is done, according to Google.
According to Google, each app is scanned for malware and other exploits before it ends up on the Play Store.
But we've noticed that scans don't always help, and every app you download could contain malware or other unknown exploits.
To combat this, Google tests each app on an Android device. That is, it installs it normally from the Play Store in a normal device environment. Then it waits, collecting the information transmitted between the device and Google's servers.
This way engineers can see if the application is behaving suspiciously or doing things it is not allowed to do by the security settings or protocols (without permission).
If an app tries to disrupt communication between Google servers and the device, engineers analyze the connection details and discover what the app installed.
It should be mentioned that the above is one of the many ways that Google uses to protect Android users.
However, we should add that none of these processes are perfect and you can still download apps with malware from the Play Store.
