It may have taken four months, but Microsoft has finally released Surface Pro 8 configurations with LTE modems. Only available as the Surface Pro 8 for Business, LTE configurations start at US$1,299.99. Microsoft has chosen the old Snapdragon X20 LTE modem for the Surface Pro 8.
https://www.notebookcheck.net/Microsoft-starts-selling-the-Surface-Pro-8-with-LTE-modems-starting-at-US-1-299-99.592072.0.html