In the last two decades, immunotherapy has emerged as a leading treatment for advanced renal carcinoma cancer (more commonly known as kidney cancer). This therapy is now part of the standard of care, but it doesn’t work for all patients, and almost all patients, no matter how they respond initially, become more resistant to treatment over time. The immune system plays a critical role in kidney cancer disease progression and in response to therapies, and so a fundamental challenge in the field is to understand the underlying “immune circuitry” of this disease.