  The impact of recent LHC top-quark pair production single differential cross
section measurements at 13 TeV collision energy on the structure of the proton
is explored. In particular, the impact of these high-precision data on the
gluon and other parton distribution functions (PDFs) of the proton at
intermediate and large partonic momentum fraction $x$ is analyzed. This study
extends the CT18 global analysis framework to include these new data. The
interplay between top-quark pair and inclusive jet production as well as other
processes at the LHC, is studied. In addition, a study of the impact of scale
choice on the theory description of the new 13 TeV $t\bar t$ measurements is
performed.
