CX3CR1 and non-small cell lung carcinoma: In addition, CX3C chemokine receptor 1 (CX3CR1), a marker of T-cell differentiation, was investigated for its role in predicting immunotherapeutic responses by Yamuchi et al. Peripheral blood mononuclear cell (PBMC) samples from 36 NSCLC patients treated with pembrolizumab or nivolumab were analyzed, and researchers found that positive clinical outcomes were correlated with increased frequency of the CX3CR1-positive CD8+ T cells in circulating blood [153].