The biomanufacturing industry has experienced significant transformations in the past 10 years, driven by changing industry trends and rapidly maturing new technologies. However, the pace of process monitoring technology development has lagged behind. This review focuses on the current major gaps in critical monitoring technology required for industry advancement, with a particular focus on single-use biosensors. There is a large unmet need for single-use biosensors in upstream and downstream processing as the industry transitions to single-use bioreactors. Emerging fields like cell and gene therapy that are still lacking numerous satisfactory at-line product characterization sensors will also be covered.