I’ve been working on-and-off for a while now on adding tile-based point cloud support to Cesium.
It seems to be working well enough at the moment that I’ve gone ahead posted my fork: https://github.com/radiantbluetechnologies/rialto-cesium.
It is based on Cesium 1.10, uses AGI’s old point-geometry branch for the point support, and adds a new (simple, naive) quadtree-based provider for handling the tiles. It requires a TMS-like point cloud tile server, which is also now posted: https://github.com/radiantbluetechnologies/rialto-geopackage.
See the READMEs in these two repos for details on building, running, etc. I’ve included a stripped-down, sandcastle-style demo app.