Fig. 1

Summary of liposomal drug delivery system and immune checkpoint blockades. a EPR effect associated with liposomal drug delivery, liposomes with a diameter between 10 and 200 nm would preferably accumulate at the tumor site. b The process of T cell activated by APCs, and T cells led to cancer cell death. c T cells are inhibited by immune checkpoints, which leads to tumor immune escape. d ICB-modified liposomes reactivated T cells, and the reactivated T cell, together with tumor locally released drugs, led to cancer cell death. e Immune checkpoints’ ligand and receptors. PD-1/programmed cell death ligand 1 or 2 (PD-L1/2), CTLA-4/CD80/CD86, TIM-3/galectin-9 (GAL-9), lymphocyte-activation gene 3 (LAG-3)/major histocompatibility complex class II (MHC II), B and T lymphocyte attenuator (BTLA)/Herpes virus entry mediator (HVEM), V-domain Ig-containing suppressor of T-cell activation (VISTA)/V-set and immunoglobulin domain containing 3 (VSIG-3). f Representative structures of liposomal drug delivery system (liposomes, exosomes, and exosome mimetics). It was created with BioRender.com. EPR enhanced permeability and retention, APCs antigen-presenting cells, TCR T cell receptor, IFN interferon, TNF tumor necrosis factor, ICBs immune checkpoint blockades, PD-1 programmed cell death protein 1, CTLA-4 cytotoxic T-lymphocyte-associated antigen 4, TIM-3 T cell immunoglobulin domain and mucin domain 3, TME tumor microenvironment, DNA deoxyribonucleic acid, RNA ribonucleic acid