  We describe the latest results obtained by the CMS Collaboration on top quark
spin and polarization properties. The top quark spin asymmetry is measured both
targeting single-top quark production in the $t$-channel and single-top quark
production in association with a Z boson. Additionally, all the independent
coefficients of the spin-dependent part of the top quark-antiquark production
density matrix are measured and the results are extrapolated to the
High-Luminosity LHC scenario.
