Photodynamic therapy (PDT) is an effective modality for cancer treatment where light is used to activate photosensitizers to produce toxic radicals, by direct destruction on cancer cells, tumor vascular damage, and initiation of immune response. However, the immunity induced by PDT is often inadequate to prevent systemic tumor control or tumor recurrence, because of immunosuppressive mechanisms involved in tumor microenvironment. Cancer immunotherapy is a recent discovered anti-cancer treatment, which aims to train immune cells by targeting immunoregulatory mechanisms to achieve tumor eliminating effect, such as PD-1/PD-L1, CTLA-4, indolamine-2,3-dioxygenase (IDO), etc. IDO is an enzyme that catabolizes tryptophan to kynurenine, and recruits immunosuppressive immune cells into tumor to suppress immune system. Therefore, synergizing PDT with cancer immunotherapy targeting IDO holds great potential in anti-cancer therapies. In the first chapter, we developed PPF nanoparticles (PPF NPs) for simultaneous PDT and immune checkpoint blockage therapy at an optimal rate, which is consisted of two nanocomponents, PLGA-PEG nanoparticles carrying IDO inhibitor, NLG919, and zinc hexadecafluoro-phthalocyanine (ZnF16Pc) encapsulated in ferritin. When tested in murine melanoma tumor model, we found that the treatment caused excellent tumor suppression while eliciting a strong anticancer immunity that effectively rejected a second inoculation with live cancer cells to prevent tumor relapse. Except the involvement in cancer treatments, nanomedicines can also be applied in anti-inflammatory therapies, either as carrier to deliver anti-inflammatory agents to lesion or itself to against inflammation. In the second chapter, we developed dopamine melanin nanoparticles (DM NPs) to scavenge free radicals for osteoarthritis treatment. Unlike small molecules, DM NPs, with the size of ~110 nm, showed prolonged retention time in the joint, sustained radical suppression, great inflammatory cytokines management, slowed down the cartilage degradation. In the third chapter, we designed Tanshinone IIA loaded PLGA-PEG nanocarrier for anti-inflammatory purpose. Tanshinone IIA, an effective anti-inflammatory drug, tends to aggregate together under aqueous solution, which lower its administration effectiveness, bioavailability, and may cause side effects. Owning to the hydrophilicity given by PLGA-PEG NPs, hydrophobic Tanshinone IIA has the possibility to effectively reach to the lesion with enhanced stability and bioavailability for ischemic stroke treatment.