There seem to be multiple definitions. I'm specifically talking about human trafficking the way it is described in the article: people either being moved again

There seem to be multiple definitions. I'm specifically talking about human trafficking the way it is described in the article: people either being moved against their will or tricked/forced into a situation where they are being held against their will (e.g. by taking their papers and forcing them to "pay off" their debt as sex workers). This meaning is called "Menschenhandel" (literally "trade of humans") in German. Calling illegal migration "human trafficking" isn't particularly helpful though it's probably a valid use of the term (the analogy being drug trafficking, or the illegal transfer of people or objects across borders).