‘s probiotic system for localized PD-L1/CTLA-4 nanobody delivery (101) and Chowdhury et al.’s tumor microenvironment-responsive E. coli strain releasing CD47-blocking nanobodies, which collectively enhance T cell infiltration, induce tumor regression, and inhibit metastasis in preclinical models (102). Here, CTLA4 is linked to neoplasm.