To clarify the coupling mechanism of time delay and spatial diffusion during CD8⁺T cell immune response, this paper constructs a time-delay reaction-diffusion model. By means of stability analysis and bifurcation theory, the basic number of rebirths of viral infection and the conditions for the existence of various equilibrium points were clarified. The findings suggest that when the hysteresis exceeds the critical threshold, Hopf bifurcation is induced, causing the system to shift from a virus-cleared state to a periodic oscillation mode, and Turing instability prompts the formation of spatial patterns when the viral spread rate is significantly faster than that of T cells. The coupling effect between time delay and diffusion can give rise to more complex spatiotemporal dynamics. The findings illustrate the key regulatory role of immune delay and spatial heterogeneity in infection outcomes.