R is a programming language intended for use for statistical analysis. Additionally, it can be utilized in an object-oriented or functional way. Specifically, it is an implementation of S, an interactive statistical programming language. R was initially released in August 1993. It is maintained today by the R Development Core Team.
RStudio is an incredibly useful Integrated Development Environment (IDE) for writing and using R. Many data scientists use RStudio for writing R, as it provides a console window, a code editor, tools to help create plots and graphics, and can even be integrated with GitHub to support version control.
While R does share some functionality with Microsoft Excel, it allows you to have more control over your data, and you can add on a variety of packages that allow statistical functionality out of the box—you won't have to build a formula to conduct a survival analysis; you can just install the survival package and use that!