Immune-based identification of cancer patients at high risk of progression

•Methods to analyze and quantify the composition of the tumor microenvironment.•Prognostic impact of tumor infiltrating immune cells determined using these methods.•Poor prognosis based on functional orientation of tumor infiltrating lymphocytes.•Identification of a high risk group of renal cell cancer using circulating leukocytes. Tumors are highly heterogeneous structures where malignant cells interact with a large variety of cell populations, including a clinically-relevant immune component. We review and compare the most recent methods designed to analyze and quantify the composition of immune and stromal microenvironment of tumors and discuss their use in identification of patients for high risk of progression. If the impact of the various immune components on patient's relapse share common rules in most malignancies, clear cell renal cell tumors behave differently with regards to immunity. We focus on this specific pathology to show how the tumor interacts with the host's immune system and how this intricate relationship shapes the clinical outcome.