This illustration highlights the fact that stromal dynamic reciprocity, between CAFs and ECM, controls CAF functions through mechanisms that alter numerous aspects of tumorigenesis such as tumor immunity, systemic inflammation, angiogenesis, metastasis, tumor growth and local neoneurogenesis (i.e., de novo microenvironmental innervation). The illustration includes a partial list of CAF functions as well as some of the mechanism by which these functions are achieved. The illustration highlights the fact that ECM regulated CAF function results in: secretion of distinct key factors, alteration of the metabolic state of the tumor, and the generation of a remodeled interstitial ECM, which together are active participants of all aspects of tumorigenesis. Note that this illustration was inspired by a figure displayed in Sahai et. al., Nat Rev Cancer 2020 [77]. Illustration by P. Ovseiovich, Mexico, DF.