Jessica De Gouw's Huntress hasn't been seen on Arrow since season 2 but all that could change in the show's sixth season. Speaking to Comic Book Resources, executive producer Marc Guggenheim has this response when asked about De Gouw's potential return. “I want to say, ‘Absolutely [to Huntress returning].’ Jessica De Gouw has expressed an absolute willingness to come back. Jessica’s a favorite actor of mine, and the Huntress is a favorite character of mine. I want to make it happen in Season 6. We’ve got some plans for the later half of the year that I think she will fit into really well, so we’ll see.”
Going by Guggenheim's hesitancy, it sounds like there are currently no plans for Helena to show up in Arrow's first half but all that could change after the show's mid-season break. Many CW DCTV fans have expressed enthusiasm for the character's return, with some going so far as to suggest that she should board the Waverider on Legends of Tomorrow. With De Gouw's schedule now open thanks to WGN's cancellation of Underground, perhaps something can be worked out?