Recently (and still in many cases) "turn down the immune system" was the treatment for most cancers. Of course, the purpose of anti-cancer drugs isn't to turn down the immune system. It just happens that the side effect of drugs that target cancer cells also target other rapidly-dividing cells like hair, endothelial, and immune cells.

In fact, chemotherapy drugs like Methotrexate are prescribed - at lower doses than for cancer patients - to people with Lupus and other autoimmune diseases.

There are similar challenges with cancer and autoimmune diseases, so progress in one might help progress in the other.

From the article: "They are now working to find ways to deliver these molecules safely and effectively to people." This is a challenge for many potentially effective cancer treatments as well.