If you use non-exempt cookies and you have EU-based users, you're required by both by law, and by law-abiding third-parties such as Apple and Google, to comply with legal requirements under the ePrivacy Directive (Cookie Law) and the GDPR. This generally means having valid cookie policy and cookie consent management solution in place.
Additionally, if you monetize your app or it's content by running third-party ads, you should also consider meeting industry standards by:
- utilizing IAB's Transparency and Consent Framework (which allows users to set advertising preferences and communicates consumer consent across participating ad networks); and
- collecting explicit consent to Google personalized ads.
Failure to do so can result in limited ad network access and, ultimately, a decrease in ad revenue.