Why am I downloading the app this way?
Google does not allow regulated gambling apps in the Play Store, and playing on mobile web is not available.
This will launch a security prompt.
Trust dksportsbook.apk file
Don't be alarmed, this is simply a necessary step to install any app outside the Google Play Store.
If prompted, navigate to settings and allow installs from your current source.
Once downloaded, you can open the DraftKings Sportsbook app and start betting!