The human microbiota comprises several microbial communities, which play key roles in maintaining host health, especially through enhancing immunity. Therefore, we aimed to examine the influence of the microbiota on immune function, particularly the mechanisms through which these microbes modify immune responses and provide protection against disease. We found that commensal bacteria maintain mucosal barrier integrity, control mucosal immune responses, and produce antimicrobial peptides. This helps protect the bloodstream and digestive tract from dangerous bacteria and antigens. Notably, the majority of human microflora are located in the gut. Research has shown that using synbiotics, which contain both probiotics and prebiotics, increases the effectiveness of microbiota-based treatments in altering immune responses and reducing immunological disorders because they result in synergistic benefits that increase the persistence and activity of microbes in the digestive system. Prebiotics typically consist of indigestible plant cells that promote the development and activity of healthy bacteria in the large intestine. They help strengthen the immune system by facilitating the proliferation of advantageous microorganisms such as bifidobacteria and lactobacilli. Additionally, prebiotics provide fermentation substrates for the production of short-chain fatty acids (SCFAs), which have anti-inflammatory properties, regulate immune cell activity, and maintain intestinal homeostasis. Microbiota-based supplements provide new possibilities for therapeutic intervention through the prevention and management of immune-related diseases. Insights into the intricate connection between the immune system and the microbiota have substantial implications for human health and highlight new opportunities for enhancing immunity and preventing disease.