CTLA4 and breast cancer: Furthermore, the comparison of expression levels of the candidate immune checkpoints within the two LMI groups manifested that PD-1, CTLA4, CD96, VSIR, TIGIT except PD-L1 were significantly augmented in the low-LMI group (Figure 6C), which hinted that BC patients with lower LMI might acquire a more enhanced response to immunotherapy targeting the checkpoints above.