The term "Boomer Shooter" has become prominent in recent years. Similar to Soulslike and the now-extinct term, Doom Clone, it's a somewhat nebulous label that typically is employed in a more "know it if you see it" kind of way. More games that fit into this strange subgenre have begun to crop up, a large portion of them under the publication of New Blood Interactive.
Source:https://www.cbr.com/retro-fps-what-is-a-boomer-shooter/