Invariant yield of $\mathrm{Z} \rightarrow \mu^+\mu^-$ divided by $\left< T_{\rm AA} \right>$ in the rapidity range $2.5 <\ycms^{\mu\mu} <4.0$ measured in Pb--Pb collisions at \fivenn in the centrality class 0--90\%. The vertical dashed band represents the statistical uncertainty of the data while the green filled band corresponds to the quadratic sum of statistical and systematic uncertainties. The result is compared with the previous ALICE result in the same collision system (the data of the earlier result are included in this analysis)~ , with CT14~ free-nucleon PDF calculation and with several NLO pQCD calculations including nuclear modification of the PDFs.