Moreover, it is known that ECM deposition by CAF, including different collagens, increases tumour stiffness and forms a barrier that impedes T cell access into the interior of the tumours, negatively impacting the efficacy of current immunotherapies.36 In this sense, analysis of CD4-positive T cells showed that these cells are localised in the surroundings of iCCA tumours in this animal model. Here, CD4 is linked to neoplasm.