NT5E and colorectal carcinoma: CAFs in human CRC tissues constitute the major population expressing CD73, a molecule acting as an immune checkpoint to suppress immune activation through the A2A receptor, and importantly, CD73 expression on CAFs is enhanced via A2B-mediated feedforward circuit triggered by tumor cell death, which enforces the CD73 immune checkpoint and consequently counteracts the antitumor immunity in CAF-rich CRC (Yu et al., 2020).