I've heard many an anecdote of soldiers deployed for months in male-only settings who could smell that a woman had arrived on base. They weren't able to describe what they smelled, or how they knew it was a woman, but they just knew.
In the books of the former Navy SEAL Richard Marcinko (he sadly died in Dec 2021), it is repeatedly stressed that soldiers shouldn't use any cologne or indeed any perfumed soap, because these smells carry a long way in the wild. The plainest soap possible and that's it.
In About Face: The Odyssey of an American Warrior (1989), David Hackworth mentions about being on patrol in the Korean war:
None of us used repellent (Chinks could smell it as easily as after-shave, soap, tobacco, and toothpaste); we couldn’t slap at them (noises traveled loud and far at night). So we waited and reluctantly contributed our blood.
and about poor discipline in Vietnam:
Guys were using soap, toothpaste, and shaving cream before operations. They were smoking and wearing mosquito repellent on patrol.
