Have a look at a demo of an open-source Unity app that lets users stream and display 3D point clouds on HoloLens.
This application lets users stream point clouds to a HoloLens and render them. You can combine it with the team's other tool, LiveScan3D, for viewing 3D data captured in real-time or pre-recorded data.
First, to get started you need to install LiveScan. Then, you need to launch LiveScan, connect a client and open the live view window. Proceed by launching the Unity application on the same machine as the server.
"If you got this far, getting it to work on Hololens should be easy, just make sure you deploy the app using XAML UWP build type instead of D3D," wrote the developer. "Once you deploy and start the app on Hololens all you need to do is input the IP number of the server and you should see the point cloud. If there are issues try rebuilding NetworkCommunication in the Release mode, the resulting dll files should be automatically copied to /Assets/Plugins/x86/"
You can learn more about the project here.