$p_{\rm T}^{\text{iso, ch}}$ distribution for narrow clusters with $0.1< \sigma_{\text {long, }5\times 5}^{2}< 0.3$ for $p_{\rm T} > 16$ GeV/$c$, in pp (bottom left frame) and Pb$-$Pb collisions in two centrality classes, $0-10$% central (top left frame) and $70-90$% peripheral (top right frame), with $R=0.2$ (black bullets) and $R=0.4$ (blue squares), in data (full markers) and simulated PYTHIA 8 $\gamma$$-$jet (open markers), embedded into data in the considered centrality class for the Pb$-$Pb collision case.