Further studies are warranted to confirm the hypothesis that high CX3CL1 expression contributes to increased benefit from ICI in lung adenocarcinoma, to reveal the origin of CX3CL1 that could either be expressed by the tumour cells or by cell of the TME and to decipher the connection of tumour genetics and CX3CL1 expression. The gene discussed is CX3CL1; the disease is lung adenocarcinoma.