Traditional proteomics assays require large pieces of tissue or a large number of cells, and the results can only reflect the overall level of protein expression. However, with our in-depth understanding of the tissue microenvironment, we need to perform precise proteomic analysis of ultra-trace samples such as primary single cells or single cell types to reveal protein expression signatures across different cell types. In this way, we are able to identify which cell types and protein targets play an important role in specific physiological or pathological states. The cell type proteomics test launched by BayOmics has achieved high-depth proteomic analysis of nanogram-scale samples through a combination of advanced technologies such as flow cytometry, SISPROT sample preparation technology, and high-resolution mass spectrometry, opening up a new horizon for us to explore and study the mysteries of life from more nuanced clinical samples.