However, with an overwhelming number of terminal patients who fail to respond durably to immunotherapy, it is urgent to look into the microbial colonization with practical utility in tumor management, especially ICIs such as PD-1/PD-L1 inhibitors and cytotoxic T-lymphocyte associated protein 4 (CTLA-4 blockades), to reactivate anti-tumor immunity. The gene discussed is CTLA4; the disease is neoplasm.