FAP and cancer: For example, fusing a non-α IL-2 mutein to an antibody against fibroblast activation protein-α (FAP) expressed on cancer-associated fibroblasts, such as simlukafusp alfa,542 or to an antibody against carcinoembryonic antigen often overexpressed by cancer cells, such as cergutuzumab amunaleukin,543 has achieved targeted expansion of CD8+ T cells at tumor sites in preclinical models and potentiated other T cell-stimulating immunotherapies.