@mcc So Leukemia treatment involves taking chemo to eradicate the cancer and with that basically all blood forming cells in the bone marrow. These can then be replaced by donor cells. If those come from a compatible donor who carries a CCR5-Δ32 mutation and everything works out thats a cure.
Multiple issues, tho: Bone marrow transplants require a compatible donor and you will still be at risk of rejecting the donor bone marrow and have to take immunosuppressants. Your old bone marrow would have to be eradicated otherwise it would continue producing infectable blood cells. That means chemo. Chemo has a huge impact on your health and even puts you at risk of further cancers.
So it seems more like a thing for after they have the holy grail - gene therapy - working.