Browsers are already (and will be even more in the future) restricting the usage of cookies across site boundaries to protect users from privacy invasion techniques. The problem is that legitimate OAuth and OpenID Connect protocol interactions are from a browser’s point of view, indistinguishable from common tracking mechanisms.
This affects front-channel logout notifications (used in pretty much every authentication protocol—like SAML, WS-Fed and OpenID Connect), the OpenID Connect JavaScript session management, and the “silent renew” technique that was recommended to give your application session-bound token refreshing.
To overcome these limitations, we need the help of an application back end to bridge the gap to the authentication system, do more robust server-side token management with refresh tokens, and provide support for more future-proof mechanisms like back-channel logout notifications.