CD28 and non-small cell lung carcinoma: Considering the critical role of the CXCL13/CXCR5 axis in modulating lymphocyte infiltration [56, 57], our evidence that intra-tumor PD1+CD28− TRM possess highest CXCL13 chemokine, while memory stem-like marker CXCR5 [58] is mostly expressed by CD28+ (CD103 low) T cells (Fig. S9), favours a scenario of CD28−CXCL13+ T cells attracting memory reservoir CD28+CXCR5+ T cells within the tumor site in our NSCLC setting.