Since the start of the 21st century, immunotherapies geared to treating cancer have continued to be refined. After a slow decline in cancer mortality rate during the last few decades, the SARS-CoV-2 pandemic is now expected to possibly increase advanced cancer stage and mortality in the future, due to delayed diagnosis and treatment resulting from recent reorganization in healthcare. Thus, the development of new cancer immunotherapies has never been more urgent. Novel research focusing on MOTO-CARs or CAR-Ms may have particular importance in revolutionizing CAR-T cell therapy. The following mini-review outlines a brief history of immunotherapy discoveries and new treatments against cancer, and reports the recent progress in checkpoint inhibitors, cancer vaccines, CAR-T cell therapies, and other major immunotherapies.