Processes with more than one boson in the final state are interesting because they can provide information on different aspects of Electro-Weak High Energy Physics. The non-abelian structure of the theory can be tested through the measurement of the strength of the couplings, while possible deviations from the theoretical prediction can hint to new physics effects. Some of the most recent results obtained by the CMS collaboration exploiting the data collected between 2016 and 2018 are presented in this note. The very high statistics that has been recorded, close to 140 fb$^{-1}$ , opens the path to the precision study of processes that were not accessible until now.