Personally, the biggest difference between targeted drugs and traditional chemotherapy drugs is that the latter is aimed at the whole tumor cells and intervenes around the biological characteristics of infinite proliferation of tumor cells, with the foothold of "fruit"; Targeted drugs focus on the "causes" of these biological characteristics during the development of tumor cells, such as CDK protein participating in proliferation regulation and VEGF affecting supply and metastasis. Obviously, the rise of targeted drugs is bound to benefit from human understanding and in-depth understanding of the molecular biological mechanism in the process of tumor occurrence and development. Without the molecular basic research of DNA, signal protein pathway and epigenetic modification, targeted drugs could not appear. However, the outer definitions of targeted drugs and chemotherapy drugs seem to be unclear enough. In general, FDA approval of the listing of rituximab from 65438 to 0997 is the key point of the rise of targeted drugs. As far as the current situation is concerned, the data of IMS20 14 show that monoclonal antibodies and protease inhibitors account for 65% of the global anti-tumor drug market, so it can be said that targeted drugs are the mainstream direction of anti-tumor treatment at present. In China, the total share of biological drugs and small molecule targeted drugs is less than 10%, which is far lower than that of alkylating agents and antimetabolites in chemotherapy drugs (24.5%), and even lower than that of plant drugs (19.3%), not to mention that the biggest problem faced by targeted drugs with China characteristics is how to overcome drug resistance. After all, the occurrence and development of tumor is a very complicated multi-factor process, and all kinds of compensatory feedback will cause drug tolerance. I think the way to overcome it is nothing more than developing multi-target inhibitors (but side effects may come up) and combining drugs (expensive). In addition, the combination with molecular diagnosis and immunotherapy are also two main directions that can be foreseen. For example, PD- 1/PD-L 1 inhibitors and other immune checkpoint inhibitors.