The comedian suffered from sarcoidosis, an inflammatory lung disease that produces tiny lumps of cells in the body's organs, but had said the condition went into remission in 2005. He recently was hospitalized and treated for pneumonia, which his publicist said was not related to the disease.
More at Fox News.
Just because he was funny as all get out, here is one of his clips, via Youtube (link is to more than one of his clips, enjoy them all.)
RIP Bernie Mac.