One disease that arises from unchecked cell growth and proliferation is cancer. Many cancer types now have lower death rates as a result of early diagnosis techniques. Still, cancer is the second leading cause of mortality globally, after cardiovascular illnesses. Consequently, the major goal of cancer research has been to provide more potent therapies in order to lower the number of cancer-related deaths. Acquiring a deeper comprehension of the molecular pathways within cancer cells has led to changes and evolutions in the treatment of cancer. Developing therapy modalities with the highest response rate and the fewest adverse effects is the top objective for research. In this regard, immunotherapies have ushered in a new phase of cancer therapy. The future of next-generation therapeutic approaches is summarized in this article by presenting the most popular immunotherapy techniques. According to recent research, biological therapies that target the tumor microenvironment specifically may engage the immune system. Clinical trials have demonstrated significant progress in the use of immune cells—particularly T cells, which are essential for cell-mediated immunity—for the treatment of malignant tumors. As a result, the treatment of cancer through therapeutic approaches and developmental strategies is the main subject of this article. The immunomodulatory response, the role of important tumor-infiltrating cells, the molecular elements, and prognostic biomarkers are highlighted in this review. Recent developments in treatment approaches are also covered.