Healthcare always plays an important role in human life. All stakeholders, including physicians, nurses, patients, life insurance agents, etc., may easily access patients’ medical information, credit goes to cloud computing, which is a key factor in this transformation. Cloud services provide flexible, affordable, and wide-ranging mobile access to patients’ Electronic Health Records (EHR). Despite the immense advantages of the cloud, Patients’ EHR security and privacy are key concerns, like real-time data access. These EHR data can be useful in finding and diagnosing chronic diseases like cancer, heart attack, diabetes, etc. Due to the severity of these diseases, most of the population is dying because of the lack of prediction techniques in the early stages of diseases. Hence, it becomes one of the most promising research problems to analyze and find solutions to overcome this loss. This work includes a review of e-healthcare-related research studies that can aid researchers in understanding the drawbacks and benefits of current healthcare systems that use machine learning, blockchain technology, and other components to ensure privacy and security.