The microbiota may interact with the tumor microenvironment, influencing the responses to anti-EGFR or anti-angiogenic therapies; thus, in metastatic disease, chemotherapy is supplemented with targeted therapies against EGFR or VEGF, and newly approved combinations—encorafenib + cetuximab for BRAFV600E, adagrasib + cetuximab for KRASG12C, and trastuzumab deruxtecan for HER2 positive—expanding the options in advanced lines [131,132,133]. This evidence concerns the gene ERBB2 and metastatic neoplasm.