I often see people using Tarot for "shadow work" and even though I've not studied anything in depth about the process of doing this, I do have some thoughts about it. I'm familiar with Jung's concept of the shadow, so that's what I imagine is meant by "Tarot shadow work" only rather than being done with a therapist, the work is done using Tarot cards presumably for oneself, but I suppose it would be possible to try to help someone else by doing readings for them. Helping someone else isn't something I'd do because I'm not a licensed therapist and a licensed therapist is the only one who should use the cards that way but onward and upward.
When I was younger, I took a college course on creativity. One of the suggestions the professor made was for us to keep a dream journal in which we'd record our dreams each night. I've never remembered my dreams unless they were extremely vivid or nightmarish, so keeping a dream journal was a challenge in the first place. It didn't work out for me very well so I abandoned the idea, thinking that since our subconscious deals with issues behind the scenes without our being aware, I'd be better off just leaving my subconscious to do its work without me peering over its shoulder at every opportunity.
I think doing shadow work with the cards might also be on my list of things best left to others along with the dream journal that's forever gathering dust in my head. There's been a lot of emotional trauma in my life and whatever my shadow is hiding might be a big old Pandora's box that shouldn't be opened without a professional therapist. Tarot is a valuable tool but I believe it needs to be used with discretion, whether reading for ourselves or for others. I think it's possible to step off the deep end without meaning to if we're indiscriminate in its use.