  The CMS experiment at the LHC has started data taking in Run 3 at a
$\mathrm{pp}$ collision energy of $13.6~\mathrm{TeV}$. In preparation for Run
3, detector systems, such as Pixel Tracker, HCAL and CSC, have been upgraded
due to radiation-induced detector aging or to improve performance. A new GEM
muon detector layer was also installed. The High Luminosity LHC, will provide
unprecedented high luminosity and pileup conditions which require more
extensive upgrades under the CMS Phase-2 upgrade project. Fully new tracker and
high granularity endcap calorimeter will be installed, as well as additional
muon detectors and MIP timing layer. Most current detector electronics will be
replaced to handle higher triggering rate of up to 750 kHz and increased
latency. The upgrades performed for Run 3 as well as planned Phase-2 upgrades
and their current development status are summarized.
