CCL19 and lung cancer: Elevated levels of CCL19 improved ICB therapy outcomes and increased patient survival.171 The levels of CCL21 in peripheral blood also positively correlate with the efficacy of ICB therapy, with CCL21 expression observed in TLS-like areas.262 In lung cancer patients with a history of smoking, they have higher levels of TLSs and T cell infiltration, which is attributed to tobacco stimulation increasing CCL21 expression.