KLRK1 and metastatic colorectal cancer: NKG2D CAR-NK cells have shown improved cytotoxicity and early signs of safety in metastatic colorectal cancer (Xiao et al., 2019; Li et al., 2025; Wang et al., 2025), while iPSC-derived MUC1-CAR-NK cells selectively eliminate MUC1+ oral tongue carcinoma with minimal toxicity (Lin et al., 2024).