Fig. 1. Schematic illustration of the tumor acidity activatable and Ca²⁺-assisted immuno-nanoagent (CaIPC) for enhancing breast cancer therapy and suppressing cancer recurrence. The preparation of the Ca²⁺-assisted immuno-nanoagent (a). The immune regulatory functions of the released immune stimulants (CpG ODNs and IDOi) and Ca²⁺ in detail (b). Intravenous injection of the Ca²⁺-assisted immuno-nanoagent into tumor-bearing mice for treating breast cancer and suppressing cancer recurrence (c).