Hi,
I was wondering if there was any plans to introduce the equal Earth projection beside/instead the Mercator view. Since it has been voted today (and was a subject for a very long time), it would be nice to see this in Cesium 
Thank you.
There is a pending PR with generalizations for the projection handling. This is essentially reviving a PR that was opened 7 years ago, but closed and never merged. I recently commented in this PR pointing out the importance of supporting more than mercator, at Add support of Proj4JS & custom map projections by mickae1 · Pull Request #13471 · CesiumGS/cesium · GitHub
When people are asking for new features in Open Source projects, there’s some sort of ‘running gag’ to reply with “Pull Requests welcome!”. It’s not always applicable, though.