Cancer immunotherapy: the art of targeting the tumor immune microenvironment.

For many decades, cancer treatment has been strongly directed toward the development of cytotoxic and cytostatic drugs, quite often leading to disappointing results due to the inter- and intra-tumoral heterogeneity. Lately, this intra-cellular look has given way to the understanding of the tumor microenvironment, thus enabling modification of the immunological dynamics between tumor cells and their host. An era of new drugs aiming to unlock the host immune system against tumor cells is steadily increasing.