Interestingly, both CD39+ populations (figure 4B,C) show upregulated expression of the tissue resident marker ALOX5AP as well as CXCL13 expression, which has been described to be a feature of exhausted TILS and CD103+ TILS in cancer,13 21 co-occurring with B cell recruitment and beneficial tertiary lymphoid structure (TLS) formation, in line with our flow data showing increased B cell frequencies in the TME of NSCLC (online supplemental figure S12). Here, CXCL13 is linked to cancer.