Answer:
In humans, CRISPR research has been done in cells in the lab, model animals such as mice, and in a few cases for treating diseases.
To treat diseases in humans using CRISPR (which has only really been done in the last year or so), the cells that are a problem are edited (e.g. in blood disorders you can remove the cells, edit them, and put them back into the patient).
However, this work does not alter what we call the germline of the individual, that means, if the person who had a blood disease went on to have children, their gametes would still carry the original genes, not any edits (as these have been done in blood cells only)
The controversial work in China involved editing human embryos. That means that the entire genetic make up of that individual is altered, in every cell. This is controversial for a few reasons
- We don't know if this is safe
- We don't know the long term effects of CRISPR on humans
- The patients did not have a disease, instead they were (allegedly and potentially) made resistant to HIV. This is not the same as receiving treatment for a deadly disease
- It was carried out against ethical guidelines