Nightdive Studios / Atari have announced that the classic System Shock 2 (1999) is getting delisted from stores on October 10th. This means you won't be able to buy it, but existing purchases will remain so you can still download and play it.
It's not all bad news though, as the announcement on Steam noted it's going to be bundled with the newer System Shock 2: 25th Anniversary Remaster. Although, the remaster is a fair bit pricier at £23.99 compared with £6.99 for the original.
One interesting point about this is that it's part of the GOG Preservation Program, and so far GOG don't seem to have announced a change for their store but it's likely it will happen at some point. GOG did announce late last year when Warcraft I and II were removed that they've extended their compatibility promise to keep delisted games updated as well. In this case though it shouldn't matter too much especially if GOG gets them bundled together, it's at least not being completely removed like we've seen with other games in the past.