B vitamins affect the increased level of TNF-α and IL-6 in the tumor microenvironment, the activation of NF-κB factor in macrophages and the increased abundance of Bacteroides, Faecalibacterium and Prevotella, which stimulate the response to immunotherapy in NSCLC and melanoma patients. The gene discussed is NFKB1; the disease is non-small cell lung carcinoma.