Cesium for Unreal uses what kind of projection?

Cesium for Unreal uses what kind of projection? Is it latitude and longitude or Web Mercator projection? When I use latitude and longitude projection, why does it look like this?
this is the map


and this is the result

TMS server use mapserver

For a Tile Map Service (TMS), it supports both geographic (longitude/latitude) and Web Mercator projections. It expects to find a tilemapresource.xml identifying which you have, so perhaps something is going wrong there. Are there any messages in the log? Based on the appearance of your screenshot, you’re using UE4, which means you’re also using a very old version of Cesium for Unreal (because the last version of Cesium for Unreal that supported UE 4.27 was v1.24 back in April). So it’s possible you’re experiencing bugs that you wouldn’t if you were on the latest version.