CD8A and colorectal cancer: This is in line with the recent findings of Bao et al. obtained through the single cell-RNA seq analysis of the colorectal cancer patients wherein a subset of anti-PD1 (nivolumab) non-responders presented with high regulatory T cells, and very low CD8 + killer T cells and CD4 + effector (helper) T cells-- indicative of an immune-cold situation [93].