It is no the first time that Microsoft has offered a Microsoft certification exam at online events.
With Microsoft Ignite 2020 Microsoft will offer a certification exam with Microsoft Ignite Cloud Skills Challenge to all participants who complete a collection on the challenges to be defined.
The page about Ignite Cloud Skills Challenge 2020 contains information about the exams you can take and the terms and conditions here: https://docs.microsoft.com/en-us/learn/certifications/microsoft-ignite-cloud-skills-challenge-2020-free-certification- exam.
If you want to participate in Microsoft Ignite Cloud Skills Challenge use the following link: https://csc.docs.microsoft.com/ignite/registration.
NOTE: Registration will be available on September 22, 2020 at 12:00 Pacific Daylight Time (PDT).