Rheumatology is the branch of medicine that deals with autoimmune and inflammatory diseases affecting the joints, muscles, and bones. In cancer care, rheumatology can be important because some autoimmune diseases may increase the risk of certain cancers, while cancer or its treatments can sometimes trigger rheumatic conditions. Certain cancer treatments, like immunotherapy, may also cause side effects that mimic autoimmune diseases. Rheumatologists help by assessing cancer risk in patients with rheumatic conditions and managing joint, muscle, or immune-related problems that may arise during cancer treatment.