Measurement of $ttH$ production in the diphoton channel and observation of heavy triboson production with the CMS detector in pp collisions at $\sqrt s = 13\ \mathrm{TeV}$

<!--HTML--><p>We present two recent CMS results based on the full dataset of LHC Run 2. Decays of the Higgs boson to photons have been used to investigate the ttH process. A significance of 6.6 s.d. is achieved in this single channel. The product of cross section and branching fraction is measured to be $1.56^{+0.34}_{-0.32}$ fb. The sample is used to investigate the CP structure the top Yukawa coupling, and a pure CP-odd structure is excluded at 3.2. s.d. . We also present the first observation of production of three massive vector bosons. Events with 3 - 6 isolated electrons or muons, or 2 same-sign leptons and 1 or 2 jets in the final state have been used to search for $WWW$, $WWZ$, $WZZ$, and $ZZZ$ production. The combined significance reaches 5.7 s.d., with evidence for the individual $WWW$ and $WWZ$ channels. The combined signal strength is measured to be $1.02^{+0.26}_{-0.23}$.</p>