The immune system is a complex network of cells, tissues, and molecules that work cohesively to defend the body against infections and diseases. Pathophysiological conditions of the immune system, such as autoimmune diseases, allergies, and immune deficiencies, often involve intricate mechanisms of species transport and biochemical transformations. Understanding these processes can unravel the biophysical and biomechanical disruptions leading to such conditions and open avenues for targeted therapeutic interventions. This section of the review focuses on the mechanisms of chemical species transport and their implications for immune pathogenesis, emphasizing how disruptions in biochemical stability affect overall tissue biomechanics. Chemical species transport in the immune system encompasses a variety of mechanisms such as diffusion, chemotaxis, haptotaxis, and cell adhesion molecules. Diffusion plays a crucial role in passive distribution of signaling molecules. Chemotaxis refers to the directed movement of cells (e.g., leukocytes) in response to chemical gradients and is fundamental in targeting infections , while haptotaxis, the movement along a gradient of substrate-bound cues, particularly aids in tissue repair and immune cell navigation . Cell adhesion molecules, such as integrins and selectins, are vital for leukocyte migration and tissue infiltration during immune responses . Convection distributes immune cells and mediators throughout the body . Convection facilitates the dispersal of cytokines, chemokines, and other soluble factors, ensuring rapid immune responses.