In the last decade, oncology drug development has been shaped by better understanding of both molecular mechanisms and the immune system. Drugs aimed at molecular targets have taken over from cytotoxics as the new norm in oncology; the most exciting new therapies now target immune responses at the molecular level. Cancer cells mutate in a way which either makes them invisible to the immune system or suppresses it, allowing unchecked proliferation. Immunotherapies are designed to co-opt the immune system either actively or passively in order to destroy tumors. The top three best-selling drugs recently have been antibody-based, while cancer vaccines are taking time to fulfill their promise. Currently, there is increased focus on checkpoint inhibitors, leading to several new approvals internationally such as Bristol-Myers Squibb’s ipilimumab and Merck’s pembrolizumab. Although innovation in new chemical entities continues to be crucial, a lot of these new chemicals will be deployed in combination with immunotherapies in the clinic, hopefully to great success.