CHI3L1 and neoplasm: In summary, our study identifies BIT as a SMOi resistant tumor epithelial cell state defined by distinct markers such as CHI3L1. In contrast to stromal-independent BST tumor epithelium, BIT tumor epithelium is spatially localized in a distinct pro-inflammatory niche near the epidermis and actively crosstalks with proximal TREM1 myeloid cells.