How does cabin pressure vary with respect to ambient pressure during descent?
During descent, the rate of change of pressure inside the cabin of a pressurized aircraft is lower than outside (ambient).



Inside the aircraft, under active control the  cabin pressure increases from equivalent ~8000ft above sea level to ground level. In the meantime, the aircraft descends from cruising altitude which is typically much higher, also to ground level. 

Assuming the pressurization and descent start and end roughly at roughly the same time, the cabin is necessarily pressurized slower than the increase of air pressure outside in absolute terms  (e.g. psi per minute) assuming a steady pressurization profile .

Corner cases arise when the airport is at an elevation above 8000ft or so since the cabin will be further depressurized during descent. So while the relation holds in absolute magnitude , they will be of opposite sign. (until there is an airport  24,000 ft or so....)