As an individual it could mean Chief Information Officer. It could mean the Congress of Industrial Organizations, which consolidated with the American Federation of Labor to become the umbrella group of the US labor movement called the AFLCIO.
It depends, in part, on whether it is really an acronym or an initialism. Typically, if it is an initialism representing the proper name of a specific organization, you would use "the" before it (e.g., the AFLCIO, the UN, the BBC, the UAE), but if it is a true acronym, you do not (NASA, NATO). The greatest exceptions seem to be the initialisms for names of universities (UCLA, NYU), which are typically pronounced without "the." That may be more prevalent in the United States than elsewhere.
Answer:Currently, the largest Labor Union in the US is The National Education Association (NEA). The NEA traditionally started out as a Professional Union, and has evolved into a Labor Union.The American Federation of Labor AFL-CIO is not a single labor union, it isa national trade union center, and the largest federation of unions, in the US, consisting of 56 national and international unions.The American Federation of Labor (AFL) was the largest in United States History. It is still around today, and is known as the AFLCIO.