To this end, Tauriello et al. used a mouse model of MSS CRC displaying the CMS4 phenotype and TGFβ-activated stroma, demonstrating that increased TGFβ in the TME represented a primary mechanism of immune evasion and that TGFβ inhibitors rendered tumors susceptible to PD-1/PD-L1 blockade [9]. Here, PDCD1 is linked to colorectal carcinoma.