Priming of T cells in the immunosuppressed tumour-draining lymph node typically results in inadequate anti-tumour immune responses. Engineered synthetic immune niches provide an alternative non-suppressed site that is permissive to optimal T cell activation. These three-dimensional matrices incorporate synthetic T cell activating cues, which ensures controlled immune-modulation. Additional immunomodulatory substances can be locally released from these scaffolds, thereby preventing systemic side effects. My work focuses on the development of synthetic immune niches consisting of injectable polymer scaffolds. These highly promising matrices are functionalized with T cell-activation proteins and antibodies via bio-orthogonal click chemistry.