4-Ac-GABA binds to the α3 subunit of the GABAAR on the surface of CD8+ T cells, inhibiting AKT1 phosphorylation, which subsequently reduces the expression of CD8+ T cell activation markers such as IFN-γ and granzyme B, and decreases their infiltration into the tumor microenvironment (Figure 2). Here, CD8A is linked to neoplasm.