What is MD?
A Markdown table is the one people actually write by hand: pipes between the cells, a row of dashes under the header. GitHub, docs sites and half the world's READMEs render them, and their one real subtlety is that a pipe inside a code span is text, not a column break.
What is XML?
XML is the verbose, strict ancestor of most structured data formats, and it is still what enterprise systems, publishing pipelines and older APIs exchange. Tabular data in XML is usually a repeating row element with one child per column.