Left panel: double ratio of the measured ${\rm K^{\pm}/\pi^{\pm}}$ $p_{\rm T}$ spectra in central Pb$-$Pb collisions and in pp collisions at $\sqrt{s_{\rm NN}}=5.02$ TeV dilated as a function of $p_{\rm T}$ by the ratio of the $\eta$ and $\rm K^{\pm}$ meson mass (see text). Right panel: measured and parameterized $\frac{\eta}{\pi^{0}}$ ratios in hadronic collisions and central Pb$-$Pb collisions, respectively.