Cancer is a leading cause of death in people with chronic kidney disease (CKD). The incidence of CKD in patients with cancer is higher than in the non-cancer population. Across various populations, CKD is associated with an elevated risk of cancer incidence and cancer death compared with people without CKD, although the risks are cancer site-specific. The potential mechanisms for the increased risk of cancer observed in CKD, include patient factors, disease, and treatment factors. CKD has also a major impact on the treatment of cancer patients. The kidney is the primary route of elimination of many anticancer drugs. Dosing of anticancer agents according to kidney function is essential to avoid undertreatment and toxicity. Because of the systemic exclusion of patients with severe kidney dysfunction from clinical cancer trials, data are lacking to guide dosing of anticancer drugs in patients with chronic kidney disease. As a consequence, many therapies are denied to CKD patients due to their possible toxicities. An orchestrated effort by all stakeholders is required to fill the knowledge gap and improve the outcome of cancer patients with kidney dysfunction.