An example can be seen in Qatar with the building of the infrastructure for the 2022 Fifa World cup.
They attracted workers from vulnerable countries in South Asia and the middle east such as Nepal, Pakistan and Bangladesh using a “sponsorship” system.
Qatar basically pays for them to come over then they pay back the debt to Qatar while working.
However, when the workers arrives ALL their wages are witheld for the “debt” so they cannot to afford to leave.