To counteract the effect of TGF-β signaling on resistance to cancer checkpoint PD-1 blockade therapy, Martin et al. [64] developed a high-affinity, humanized antibody named SRK-181 that specifically neutralizes latent TGF-β1, but not the other latent TGF-β isoforms and exclusively inhibits the activation of only the TGF-β1 isoform. Here, PDCD1 is linked to cancer.