Overview of CMS luminosity-determination methodology in Run-2

The CMS experiment operates several detector systems dedicated to luminosity measurement. The requirements on luminosity systems and their features are summarized. The calibration methodology for nonlinear detector responses is reported. During 2015--2018 (Run-2), preliminary results of the luminosity measurement for all data-taking periods have been made public within a year of the van der Meer scans. The calibration strategy, applied corrections, and relevant uncertainties are determined for each year. This note reviews all four publications using proton-proton collisions at 13 TeV during Run-2. The calibration-related effects, common to all years, are explained and the impact on the uncertainty in the integrated luminosity is put in context.