Monte Carlo modeling and tuning studies at CMS

The Monte Carlo modeling adopted at the CMS experiment is reviewed. Choices of matrix-element generators are explained and new CMS PYTHIA8 underlying-event tunes are presented. The new tunes are obtained using minimum bias and underlying event observables exploiting Monte Carlo configurations with consistent parton distribution functions and strong coupling constant values in the matrix element and the parton shower, at leading order (LO), next-to-leading order (NLO) and next-to-next-to-leading order (NNLO). Validation and performance studies are presented by comparing the predictions of the new tunes to a wide range of different CMS measurements at 7, 8 and 13 TeV.