For a display tablet your are pointing at one location on the pen, but the pointer is showing somewhere else. It could be do to the pen being incorrectly calibrated to the display.
Most pen displays offer a pen calibration to solve this problem.
Some, like the Wacom Cintiq Pro 27 offer this claibration because they are well-calibrated when you get them.
Pen calibration is a feature found in pen displays. Pen tablets don't need the feature.
Open the XP-Pen Pentablet app
Under Work area > Screen, press Calibrate
Follow the calibration steps
Open the HuionTablet app
Under Pen Display > Working Area, press Monitor Calibration
Follow the calibration steps