have a boss/Elite icon on the minimap.

where on the map ?

Elite mob on Abandoned monastery

Elite mob that spawns infrequently.
Go to the Abandoned Monastery near Trent, go down the well, and there are 2 open caverns where the mob spawns.
Looks like this:

Not sure if the elite still spawns in the normal zone but you can find plenty of them in the 280 zone

В заброшенном монастыре в колодце, как спустились по прямой.
Справа будет как ориентир решетка: https://prnt.sc/21rjbutB9C-c