CTLA4 and neoplasm: Engineered probiotic bacteria expressing and secreting the PD‐L1 nb and a cytotoxic T lymphocyte‐associated protein‐4 (CTLA‐4) nanobody have been shown to reduce tumor growth and enhance T cell activation when administered intratumorally.[7] Compared to traditional antibodies, which are ≈150 kDa, nanobodies are much smaller (≈15 kDa) and lack an Fc region.[8] This unique structure allows nanobodies to be recombinantly produced or genetically expressed in mammalian cells.