Cancer is one of the deadliest health menaces humans have ever witnessed. It is a leading cause of human mortality. Today, it remains a main leading cause of death globally primarily due to lifestyle changes and population ageing. A total of ~12.7 million cancer cases and 7.6 million cancer deaths were reported in 2008. In developing countries, cancer accounted for 56% of cases and 64% of deaths. Tamoxifen is the most reputable and recommended specific oestrogen receptor modulator drug used for the treatment of breast cancer. In the past decade, algae have demonstrated remarkable potency for advanced life applications. They can remain a focus of interest in the coming decades because they are one of the most diverse organisms in the entire ecosystem with immense bio nutritional benefits. Algae and their extracts play a pivotal role in the pharmaceutical industry as bioactive compounds and new drugs and nutraceutical industry as probiotics and antioxidants. However, a broad range of the health benefits of these organisms remains to be explored. The present review highlights the applications and co-application of microalgal crude extracts with tamoxifen for breast cancer immunotherapy. Given that recent studies have suggested that tamoxifen is an essential and primary treatment for breast cancer, the present review focused on the identification of a new treatment approach involving the co-application of tamoxifen and microalgal extracts to provide promising anticancer activity with few side effects on normal cells. The present review includes a general background and blueprint for the use of microalgal extracts as potential and affordable treatments or adjuncts for breast cancer management.