Urinary bladder matrix (UBM) is used clinically for treatment of diabetic ulcers, abdominal wall reconstruction, soft tissue filling among other applications. Composed mainly of collagen, the material is a mix of fibrous collagen structures and sheet-forming structures characteristic of the urinary bladder matrix basal lamina. Upon application of a biomaterial in a traumatic or non-traumatic setting, there is a cascade of immune cells that react to the damaged tissue and biomaterial. Here, through the use of multicolor flow cytometry, we describe the various cells that infiltrate the UBM scaffold in subcutaneous and volumetric muscle injury model. A wide variety of immune cells are found in the UBM scaffold immune microenvironment (SIM) including F4/80 + macrophages, CD11c + dendritic cells, CD3 + T cells and CD19 + B cells. UBM induced a systemic IL-4 upregulation and a local M2-macrophage response. The recruitment and activation of these cells is dependent upon signals from the scaffold and communication between the different cell types present.