Hello, community!. This is a question that always raises some debate among the people I know who do single-cell RNA-seq analysis. I am not well versed in informatics and I would really appreciate the input of the people who face this often. After clustering cells into cell types using the available clustering algorithms, what is the most appropriate way of identifying the different cell populations?. I know that it can be done manually, but this becomes more complicated in tumors where i.e several macrophages populations appear. Sometimes is not straightforward if there is no dataset that has previously identified these cells in particular tumors. I know of the existence of CellAssign and others, but these still rely on inputting a reliable list of marker genes. Additionally sites like https://www.panglaodb.se/ have signatures generated in normal tissues, but I don't know if it is accurate to use those for tumor tissue. I would greatly appreciate any input!.