Thank you for the reply. I have read the documentation but still not sure the situation for using kernel density.
Since the density formula in ArcGIS pro just calculates the density of (x,y) location and doesn't explain for z coordinate, i think it is more suitable for 2D. In this case, i will use this tool only for 2D datasets.
Just want to make sure if i misunderstand the meaning of formula? Thank you!