Emerging research explores the intricate role of human microbiomes in tumorigenesis and systemic health. A recent Medical Oncology study implicated microbiome alterations as contributors to early-onset colorectal cancer development, emphasizing the microbiome–cancer axis. Additionally, BMC Neuroscience published findings where fecal microbiota transplants significantly modified gut bacterial compositions, improving outcomes in Alzheimer’s disease models. These insights deepen our understanding of microbial interactions as potential targets or biomarkers in complex human diseases.