BiVariate Choropleth Mapping

using Arc Map

Go to Layer Properties>Symbology

Choose -> Multiple Attributes

Choose -> Bivariate renderer

Select the two attributes you would like to map

It is a bit buggy

Probably a good idea to stick to 4X4 grid

Pick Two colors that will combine well

Click apply

Export Legend

Go to Layout view

Insert Legend

Make sure your Layer is in the box on the right side

Resize legend and export