The CMS Tracker upgrade for HL-LHC

The LHC machine is planning an upgrade program which will smoothly bring the luminosity to about 5 $\times$ $10^{34} $cm$^{-2}$s$^{-1}$ in 2028, to possibly reach an integrated luminosity of 3000 fb$^{-1}$ by the end of 2037. This High Luminosity LHC scenario, HL-LHC, will require a preparation program of the LHC detectors known as Phase-2 upgrade. The current CMS Outer Tracker, already running beyond design specifications, and CMS Phase1 Pixel Detector will not be able to survive HL-LHC radiation conditions and CMS will need completely new devices, in order to fully exploit the high-demanding operating conditions and the delivered luminosity. The new Outer Tracker should have also trigger capabilities. To achieve such goals, R$\&$D activities are ongoing to explore options both for the Outer Tracker, and for the pixel Inner Tracker. Solutions are being developed that would allow including tracking information at Level-1. The design choices for the Tracker upgrades are discussed along with some highlights of the R$\&$D activities.