B2M and colorectal carcinoma: HT-29 CRC cell lines of MMRp lineage retain B2M function compared to MMRd lines (HCT-15 and Lovo), where B2M gene defects (HLA -1 antigen presentation loss) in HT-15 cell lines instigate the most profound ICB response orchestrated mainly by PD1+ γδT cells in a coculture based drug reactivity assay (measuring Caspase3/7).