My neighbor has black mold in his house and was just told he has lukimeia(cml). could there be a connection between the two?

No connection: There is no connection between the presence of black mold and leukemia.

Mold not cause: Molds grow in damp places, can cause symptoms: nose, throat, and chest. Some make a poison (mycotoxin), most don’t. Air exposure not severe except for people with allergies, asthma, lung diseases, and immune deficiency. Don’t swallow molds. Clean up carefully. Reliable sources 1) general: https://www.cdc.gov/mold/faqs.htm 2) hurricane: https://www.cdc.gov/mmwr/preview/mmwrhtml/rr5508a1.htm