In a specific study by Lambrechts and co-workers on NSCLC, single-cell sequencing reveals T cells clusters into regulatory T cells (FOXP3+), natural killer and natural killer T cells (FGFBP2+), CD8+ T cells (CD8+, naïve, effector, resident memory or exhausted), CD4+ T cells (CD4+), and minor populations of γδ T cells (23) (Figure 2). Here, CD4 is linked to non-small cell lung carcinoma.