Now available – Azure AD B2B Collaboration Join/Leave Consent
http://cloudblogs.microsoft.com/enterprisemobility/2018/05/14/exciting-improvements-to-the-b2b-collaboration-experience/Azure AD B2B Collaboration now has an improved experience for giving partners access to business resources, but also help support organizations' obligations under GDPR. First, there is no more reliance on an email for receiving an invitation to collaborate. Now guest users can simply access the application you've invited them to. Invitees will also now see an updated consent screen with a privacy statement to accept before joining, and they can opt to leave an organization and have their account removed with a new self-service option.
Source: Azure Roadmap