This is definitely from Girls Frontline since there are multiple image sets listed in Baidu showing her dressed in the same cheongsam but with the OTs-14 "Groza" assault rifle weapon. Looking over the Girls Frontline wiki, this cosplay is definitely for the OTs-14 tactical doll. Verification this cosplay gets the OTs-14 character tag is at "en gfwiki com/wiki/OTs-14".
*followup* Also see related cosplay at /g/1603765/4220e62744/ The company really got a lot of mileage out of this dress as there are multiple discs with many hours of video. One of those sets of images almost half the size of this gallery has five hours of video. It's been awhile to see this kind of use of a garter with garter belt but with no stockings. I guess the company is just trying to flip switches of long leg collectors.