When лагерь is used by itself, it depends on context - could be a prison/labor camp, kids summer camp, a historical military reference to an army camping on a campaign, or even a refugee camp or a tourist camp. Not that different from English “camp” really.

Russian also borrowed lager bier in “лагер” (without the softening “ь”), whereas Czech and Slovak have native words for it (ležák/ležiak) with a similar (if not greater) complexity in styles to Germany.