While other HER2-targeted agents like pertuzumab, lapatinib, and T-DM1 have shown limited success in later-line gastric cancer trials, the newer antibody-drug conjugate trastuzumab deruxtecan has shown promising activity, potentially due to its potent payload and bystander effect, which might also interact differently with the immune milieu (Riccardi et al., 2023; Yu et al., 2024). Here, ERBB2 is linked to gastric cancer.