Intriguingly, FMT or gut Streptococcus enrichment in neoadjuvant chemoimmunotherapy responders may augment anti-PD-1 efficacy by boosting intratumoral Streptococcus and expanding tumor-infiltrating CD8+ T lymphocytes, explaining the association between Streptococcus abundance and extended PFS in esophageal squamous cell carcinoma trials[155]. Here, CD8A is linked to neoplasm.