The CMS Tracker Upgrade for the High Luminosity LHC

The LHC machine is planning an upgrade program which will smoothly bring the luminosity to about $5\times10^{34}$cm$^{-2}$s$^{-1}$ in 2028, to possibly reach an integrated luminosity of 4000fb$^{-1}$ 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 upgrades. The current CMS Outer Tracker (OT), already running beyond design specifications, and CMS Phase1 Pixel Detector will not be able to survive the HL-LHC radiation conditions. Thus, CMS will need completely new devices, in order to fully exploit the delivered luminosity. The new OT should also have trigger capabilities. To achieve such demanding goals, there is ongoing R\&D activity to explore the options for the Outer Tracker and for the pixel Inner Tracker. The developed solutions would allow including tracking information at the Level-1 trigger. The design choices for the Tracker upgrades have been documented in a dedicated Technical Design Report and will be reviewed along with some current highlights of the R\&D activities.