The Phase 2 Upgrade of the CMS Inner Tracker

A new silicon tracker will be built for the Phase 2 Upgrade of the CMS experiment to fully exploit the increased luminosity delivered by the HL-LHC. The innermost part, called the Inner Tracker, will be exposed to extreme conditions such as unprecedented radiation levels of 1.2\,Grad and $2.3\times10^{16}$\,n$_{eq}$/cm$^{2}$ and hit rate of 3.2\,GHz/cm$^{2}$. The new Inner Tracker relies on many novel solutions and technologies that allow for a design of a light and radiation-hard pixel detector of high performance. The hybrid pixel modules will be composed of pixel sensors with pixel size of 2500\,$\mu$m$^{2}$ and a new ASIC, designed in 65\,nm CMOS technology, developed by the RD53 collaboration. A novel scheme of serial powering will be deployed to power the pixel modules and new technologies will be used for a high bandwidth readout system. The mechanics will be lightweight, based on carbon-fibre material and two-phase CO$_{2}$ cooling. In this contribution, the design of the CMS Inner Tracker system will be presented along with the prospective design choices.