Rheumatoid arthritis is a common inflammatory disease that requires treatment with immunosuppressants to control symptoms and avoid joint destruction. Managing cancer in patients with concomitant rheumatoid arthritis poses special challenges that require close coordination of care between oncologists and rheumatologists. Potential clinical issues needing special consideration include: 1) perioperative management in patients undergoing cancer surgery, which often requires discontinuation of antirrheumatic therapy; 2) use of immunosuppressant therapies for rheumatoid arthritis, especially biologic agents that inhibit cytokine and immune pathways, which conceivably could affect immune-mediated antitumor responses (the issues are different in patients with active cancer vs those with a past history of cancer and no recurrences); 3) management in the palliative care setting; and 4) use of cancer immunotherapy, such as checkpoint inhibitor agents, in patients with pre-existing rheumatoid arthritis. We explore these clinical issues in case-based scenarios. In all cases, clinical decision making must include a careful weighing of risks and benefits of both cancer treatments and antirrheumatic therapies, with attention given to prognosis and life expectancy, quality of life, and patient preferences.