The first full-scale use of women in official front-line combat roles (as opposed to nurses or the occasional one-off who might sneak in now and then) were the
Women's Battalions formed by the Russian provisional Kerensky government in WWI (and not, as one might have guessed, by the Bolsheviks).
The formations acquitted themselves reasonably in combat, with good performance and low casualties. However, it was still only 1917 after all, so they eventually they were disbanded.
The truly bleak comedy came once the government decided they didn't like the idea after all. First they wanted to move them to non-combat roles (similar roles to US, UK, etc. in WWI and WWII), but then men in those non-combat jobs refused, saying better them than us on the front lines. Unable to figure out what to do, the government simply disbanded the units. Only when that happened, the women's battalions just hung around their camps for months, waiting for orders, because
no-one wanted to be the guy who told them.=======
For the record, the next use was not the Russians again, but the Poles, in the Russo-Polish war of 1919-1920 (which Russia lost horribly). The Poles tried to keep the women away from fighting but did train them for combat and wound up using the units when forced to in the north. This featured a lot less of the ridiculousness of the previous Russian attempt and again the woman were a credit to the uniform, fighting well.
There are cool photos of the Polish brigades!
