BAG3 and neoplasm: As previously shown using the murine anti‐BAG3 AC‐2 antibody (Iorio et al., 2019), also BAG3‐H2L4 treatment affects the tumor microenvironment resulting in a reduction of α‐SMA‐positive fibroblasts (Fig. 3B), effectively recapitulating the functional effects of the original murine version in vitro and in vivo.