AbstractRat sarcoma (RAS), as a frequently mutated oncogene, has been studied as an attractive target for treating RAS‐driven cancers for over four decades. However, it is until the recent success of kirsten‐RAS (KRAS)G12Cinhibitor that RAS gets rid of the title “undruggable”. It is worth noting that the therapeutic effect of KRASG12Cinhibitors on different RAS allelic mutations or even different cancers with KRASG12Cvaries significantly. Thus, deep understanding of the characteristics of each allelic RAS mutation will be a prerequisite for developing new RAS inhibitors. In this review, the structural and biochemical features of different RAS mutations are summarized and compared. Besides, the pathological characteristics and treatment responses of different cancers carrying RAS mutations are listed based on clinical reports. In addition, the development of RAS inhibitors, either direct or indirect, that target the downstream components in RAS pathway is summarized as well. Hopefully, this review will broaden our knowledge on RAS‐targeting strategies and trigger more intensive studies on exploiting new RAS allele‐specific inhibitors.