  A search for central exclusive production of top quark pairs
($\mathrm{t}\bar{\mathrm{t}}$) is presented using collision data collected by
CMS and the CMS-TOTEM Precision Proton Spectrometer in 2017. A data-driven
method to estimate the background from coincidences of inclusive events and
pileup protons is described, as well as the development of a Boosted Decision
Tree classifier to separate the exclusive $\mathrm{t}\bar{\mathrm{t}}$ signal
from the inclusive $\mathrm{t}\bar{\mathrm{t}}$ background. The first-ever
upper limits on the cross section of exclusive $\mathrm{t}\bar{\mathrm{t}}$ are
shown.
