The LHCb experiment at CERN has discovered a doubly charmed isoscalar tetraquark $T_{cc}$ with the quantum numbers of ccūd¯ and mass of about $3875 MeV/c^2$, decaying to $D^0D^0π^+$ through the intermediate channel $D^∗+D^0$. We present a study of its strange companions with the quantum numbers of $cc\overline{q}\overline{s}$, where $q=u$, $d$ and isospin violation is neglected.