Macbook Pros require a docking station with a Lightning USB-C port for more than one external display. One display port on the docking station may be used, but the second display cable MUST be plugged into the lightning USB-C port on the back of the docking station. Note: DisplayPort USB-C port will not work as lightning port. Must explicitly be labeled as a lightning port on the dock. 

• Cables Required
  • Display Port to Display Port, HDMI to HDMI, or USB-C DP to USB-C DP can be used for the first external display.
  • HDMI to USB-C, Display Port to USB-C, or USB-C to USB-C connected to a lightning port on the dock must be used for second external display.

Lightning Ports labeled below on the WD22TB4 Dell Docking Station

NOTE: Macbook Air only supports one external display unless an M3 chip or newer. If M3 chip or newer, configuration above can be used. 

NOTE: Some Macbook Pro models require the lid to be closed for the second external display to appear.