Beyond its establishedrole as an oncoprotein, PTP1B is emergingas a novel intracellular immune checkpoint. In T cells, its upregulation acts to limit antitumor function, andits inhibition has been shown to potentiate immunity by enhancingthe activity of both T cells and dendritic cells.,, Our bioinformatic analysis of publicly availablesingle-cell RNA sequencing data from colorectal cancer patients revealed a distinct PTP1B expression profilein colorectal tumors: while unaltered in T cells, it was significantlyupregulated in tumor-infiltrating B cells. The gene discussed is PTPN1; the disease is neoplasm.