Accumulated research corroborates the feasibility of microbial antitumor therapies, enriching the diversity of cancer therapeutics. Recently, Ferrari et al. revealed the role of postbiotics in sensitizing cancer cells to immune checkpoint inhibitors (ICIs) and synergizing immunotherapy. Particularly, phytosphingosine induces upstream MYD88/NF-κB and downstream NLRC5 activation, enhances T cell effector responses, and inhibits tumor growth.