ERBB2 and breast cancer: In our study, firstly we integrated single‐cell RNA sequencing data from more than 260,000 cells from previously published breast cancer datasets with ER‐positive, HER2‐positive and TNBC samples, determined the cell types based on the marker genes and identified the differentially expressed genes across various cell types between TNBC and ER/HER2‐positive cancers using pseudobulk analysis.