Immune cells play a major role in the development of cancer, from being able to inhibit it by secreting pro-inflammatory mediators, to assist in its development by secreting growth factors, immunosuppressive mediators, and ECM-modifying enzymes. Therefore, the ex vivo analysis of the secretion function of immune cells can be employed as a reliable prognostic biomarker in cancer. However, one limiting factor in current approaches to probe the ex vivo secretion function of cells is their low throughput and the consumption of large quantities of sample. Microfluidics provides a unique advantage, by being able to integrate different components, such as cell culture and biosensors in a monolithic microdevice; it can increase the analytical throughput and leverage it with its intrinsic low sample requirement. Furthermore, the integration of fluid control elements also allows this analysis to be highly automatable, leading to increases in consistency in the results. Here, we describe an approach to analyze the ex vivo secretion function of immune cells using a highly integrated microfluidic device.