For the period of 2016 to 2018 (Run-2),
data corresponding to an integrated luminosity of around 150 fb$^{-1}$ have been collected at the center of the mass energy of $13~{\rm TeV}$
by the CMS experiment at the Large Hadron Collider.
The data deluge allows us to perform searches and measurements of the rare processes in the top quark sector.
The latest cross section measurements and searches of the rare processes in association with a top quark pair
are presented here.