Finally, the checkpoint TIGIT has been noted to be enriched in ductal carcinoma in situ compared to invasive ductal cancers, which were more enriched for PD-L1, but the implications of this finding are currently unknown.19 There are ongoing, phase I clinical trials involving anti-PD-1/L1 ICBs combined with LAG-3 (NCT03250832; Table 1), B7-H4 (NCT03514121), or TIGIT (NCT03628677) blockade in solid tumors, with planned expansion into breast cancer. This evidence concerns the gene CD274 and breast carcinoma.