The Large Hadron Collider will undergo a luminosity upgrade targeting a peak instantaneous luminosity ranging from 5 up to 7.5$\times10^{34}$ cm$^{-2}$s$^{-1}$. The ambitious goal of the High Luminosity LHC is to achieve a total of 3000--4000 fb$^{-1}$ of proton-proton collisions at a center-of-mass energy of 13--14 TeV by 2041.
To cope with such challenging environmental conditions, the outer tracker of the CMS experiment will be upgraded using closely spaced silicon sensors (pixels and strips) to survive in the harsh radiation environment. A PS module, composed of a pixel and a strip sensor was tested at the Fermilab Test Beam Facility to evaluate its ability to provide accurate tracking information, $p_{\rm T}$ discrimination, and optimal performance at the irradiation levels expected after being exposed to the harsh conditions of the High Luminosity LHC. The results of the test and the comparison of the module performance before and after irradiation will be presented in this paper.