CD8A and colorectal carcinoma: While T-cell content is a powerful predictor in some cancer settings such as CRC, the relationship between CD8+ T-cells and ICB response is clearly complex, as many factors can govern the ability of T-effector cells to target tumour cells, including neo-antigen load, PD-L1 expression, T-cell distribution, and the presence of immune-suppressive Tregs, γδ T cells, and myeloid suppressor cells [48,49,50,51].