We've update the
shopify_app Ruby gem and
koa-shopify-auth for Node.js (used by the Shopify App CLI) to declare
Samesite=none; Secure in cookies used in third-party context. Updating your embedded apps to the newest version of these tools will prevent cookie issues after the release of Chrome 80 on February 4th, 2020.
You can learn more about Chrome's new cookie requirements and (how to update your app's cookies)[https://help.shopify.com/en/api/guides/samesite-cookies] using our guide.