Searches for non-resonant $HH$ production and measurements of the Higgs self-coupling ($\lambda$) in the channels $HH\rightarrow bbWW^*$, $HH\rightarrow WW^*\gamma\gamma$ and $VHH\rightarrow 4b$ have been presented. The analysis is based on data recorded at a center of mass energy of 13 TeV by the CMS detector during LHC Run2. The results are compatible with the Standard Model expectation. Exclusion limits on the $HH$ production cross section and on $\lambda$ have been presented.