A type of treatment that uses an immune substance, such as a monoclonal antibody, that is chemically linked to a cell-killing substance such as a toxin, radioisotope, or drug. The immune substance targets certain types of cells and the linked substance kills the targeted cells without harming other cells. Immunoconjugates are used in the treatment of cancer. Examples include antibody-drug conjugates, immunotoxins, and some targeted therapy drugs.