I recently purchased some Lolin/Wemos S2 Mini boards (the ESP32 successor to the popular Wemos D1 Mini that uses the ESP8266).
Whereas there were hardly any changes required for programming and uploading to the D1 Minis, there were several additional steps for uploading sketches to the S2 Mini.
Namely you have to hold the 0 button down and then press the RST button to put the board into a firmware update mode, before you can upload you sketch. So far so good.
My issue though was that despite apparently matching all the settings in the Wemos documentation (Get started with Arduino [S2 series] — WEMOS documentation) and being able to upload sketches, nothing would appear on the Serial Monitor. Nothing, not even garbled text. Serial monitor would remain blank.
I've been playing around and have just discovered that setting the board to "ESP32S2 Native USB" appears to have fixed the issue. Serial monitor now works. Hopefully this will help others.