The PMDG 777 for MSFS (currently 300 but future versions as well) has been added to the FS2020 plugin.

To use please download version 6.2.0 of the plugin or above from the downloads section and don't forget to add the SDK options to the 777_options.ini file.

Currently it supports most of the features of AirTrack supported by the 737, as well as AirFMC access to each of its 3 CDUs.