Under the European Genderal Data Privacy Rules (GDPR) now in place, European Union users of your site need to know if you are using cookies and what data they collect (eg Facebook pixels).
There are new apps available in the Shopify App store that will add a GDPR notification popup for European Users. Some only pop up to those with IP addresses in the EU to avoid annoying other users. Take a look at the features offered by each and decide which is the best for you.
These apps are well worth considering if there is a chance you will have EU customers on your site.
Remember to re-test your site thoroughly after adding any new apps - including on mobile, tablet, and other browsers. Make sure you can still search, add to cart, check out, and sign up to your newsletter.
As usual, please take this as a guide only, for legal advice please consult your Lawyer.