Google is officially shutting down the Google Drive app for PC and Mac. Support will end on December 11th and the app will be shut down on March 12th, 2018. There will still be many ways to access your Google Drive, but the desktop app is being phased out.
Google is replacing the Drive desktop app with Backup and Sync, which was released in July. Backup and Sync also replaces the Google Photos Uploader desktop app. G Suite users get an app called Drive File Streamer, which is a more integrated solution.
Google created the chart below so you can see which app is best for you. Most consumers will be fine with Backup and Sync.