Innate mechanisms in the tumor stroma play a crucial role both in the initial rejection of tumors and in cancer promotion. Here, we provide a concise overview of the innate system in cancer and recent advances in the field, including the activation and functions of innate immune cells and the emerging innate properties and modulatory roles of the fibroblastic mesenchyme. Novel insights into the diverse identities and functions of the innate immune and mesenchymal cells in the microenvironment of tumors should lead to improved anticancer therapies.