Fig. 1.

Anti-tumor immune response and ICIs. The induction of the effective anti-tumor immune response requires multiple steps: (I) The tumor-associated neoantigens are released and subsequently captured by APCs; (II) APCs present the captured antigens on MHCI molecules to T-cells, resulting in the proliferation and activation of T-cells, (III) homing and infiltration of activated T-cells. (IV) recognition of peptide MHC-I complexes and release of perforin and lytic granules to mediate tumor cell killing. Abnormalities in each of these steps during or after treatment can develop acquired resistance to ICI therapy