I don't think we have slums. But what about the idp camps?
Those are people temporarily displaced from their actual homes, due to conflict or environmental hazards. For example 3.7 million Ukrainians are in idps camps, you can google in any other conflict area.
Same thing in certain American states where hurricanes and floods displace people: 3 miliion infact.
https://www.urban.org/urban-wire/mo...natural-disaster-past-year-how-can-we-prepare
Otherwise those people live in normal houses.