Cancer immunotherapies have transformed oncology by utilizing the immune system to target malignancies; however, limitations in efficacy and potential side effects remain significant challenges. Nanoparticles have shown promise in enhancing drug delivery and improving immune activation, with the potential for numerous modifications to tailor them for specific environments or targets. Integrating nanoplatforms offers a promising avenue to overcome these hurdles, enhancing treatment outcomes and reducing adverse effects. By improving drug delivery, targeting, and immune modulation, nanoplatforms can unlock the full potential of cancer immunotherapy. This review explores the role of nanoplatforms in addressing these limitations and enhancing cancer immunotherapy outcomes, examining various types of nanoplatforms. Understanding the mechanisms of immunomodulation through nanoplatform deliveries is crucial. We discuss how these nanoplatforms interact with the tumor microenvironment, modulate tumor-associated macrophages and regulatory T cells, activate immune cells directly, enhance antigen presentation, and promote immunological memory. Further benefits include combination approaches integrating nanoplatforms with chemotherapy, radiotherapy, and phototherapy. Immunotherapy is a relatively new approach, but numerous clinical studies already utilize nanoplatform-based immunotherapies with promising results. This review aims to provide insights into the potential of nanoplatforms to enhance cancer immunotherapy and pave the way for more effective and personalized treatment strategies.