Peripheral blood mononuclear cells (PBMCs) are blood cells that are a critical part of the immune system used to fight off infection. However, due to the complexity of PBMCs, which contain multiple different cell types, studying the function of the individual cell types can be difficult, and often studies rely on bulk measurements. Here, we describe the analysis of PBMCs using single-cell RNA-sequencing in droplets. Data from these studies allow for the identification and quantification of the subpopulation of cells that make up the PBMC sample. In addition, differential gene expression between cell types and samples can be assessed.