These proceedings describe the measurement of the CP-violating phase $\phi_s$ using ${B_s^0\to J/\psi\,\phi(1020)}$ decays with the CMS experiment at $\sqrt{s} = 13$~TeV.
The measurement is based on a data sample collected in 2017--2018 corresponding to an integrated luminosity of 96.4~fb$^{-1}$.
A dedicated tagging trigger and a opposite-side muon flavour tagger based on deep learning techniques have been used in this analysis, significantly increasing the fraction of tagged events.
The decay width (mass) difference $\Delta\Gamma_s$ ($\Delta m_s$) between the light and heavy $B_s^0$ mass eigenstates, the $B_s^0$ average decay width $\Gamma_s$ and the CP violation observable $| \lambda |$ are also measured.
The combination with the results obtained by CMS at $\sqrt{s}=8$~TeV is also presented.