Her big question to use was "is there going to be a problem with me working here". As in "are people going to treat me like shit because I am transgender".
It was an extremely professional environment and I and my boss unequivocally said - we don't care what you are as long as you do your job and do it well.
I worked with her for probably near a year and I did not see people overtly treating her badly, making comments of any sort at all. People called her by a name that she chose and used the pronouns she wanted.
Of course I don't know her experience but I can't express how it was a 'professional' environment enough. I have never worked somewhere that was so damn... professional. This included old dudes, old women, young men and women, people from all sorts of cultures and backgrounds (UK, India, Ukraine, and all over the US, and probably more places).
People minded their own business, were polite, did not intrude upon personal matters, and while there was some jockying around sports teams - it was a place where all sorts of people and backgrounds worked. There was an extremely competent HR department, and middle management and C levels who were very serious about being professional.
I don't know - kind of a rant - hopefully her experience at my workplace was one of her better ones.
As in, "let's pretend they don't exist, ban them from anything that straight couples can do, and push them to get conversion therapy so they behave like us 'normal' folks".