Measurements of the top quark polarization and top quark pair (tt¯) spin correlations are discussed in this talk. Events containing two leptons produced in proton-proton collisions at a center-of-mass energy of s√= 13 TeV are going to be presented including a set of parton-level normalized differential cross sections, sensitive to each of the independent coefficients of the spin-dependent parts of the tt¯ production density matrix. The data were analyzed by the CMS experiment at the CERN LHC in 2016 and correspond to an integrated luminosity of 35.9 fb−1 for the first time. The measured distributions and extracted coefficients are compared with standard model predictions from Monte Carlo simulations with next-to-leading-order (NLO) accuracy in quantum chromodynamics (QCD) and from NLO QCD calculations including weak and
mixed QCD-weak corrections. All measurements are found to be consistent with the expectations of the standard model.