The current study is a review of the literature on patients with diabetes who are diagnosed with colorectal cancer (CRC), encompassing recent research on CRC and the molecular level changes occurring in these patients on the basis of varying environmental as well as non-environmental factors. It has been noted that nearly 50% of all patients undergo the systemic treatment module; however, most of them exhibit drug resistance. In addition, targeted gene therapy has also been used in treatment but has been found to be effective only in patients with a specified molecular profile (or else this might lead to an increased risk of developing resistant mutations). This has led to increasing interest among researchers in finding innovative treatment options. Metformin, a biguanide, has been widely used in treating diabetes. The drug has been reportedly used in cases of hypothesis-generating retrospective population studies of diabetic patients showing reduced incidence of cancer. Metformin helps in reduction of excess insulin levels that possess various effects on cell signaling and metabolism. Nonetheless, there is need for an in-depth study on its molecular mechanism to fill any existing research gaps.