It's not about whether they exist or not. They definitely exist.

It's about "what is life?" which is a much, much harder question to answer.

The truth is, it's a separate question. It's easy to define what a virus is, but you can debate all day about what exactly is life, and whether viruses fit into the definition that you land on.

If you're asking what a virus is, it is genetic material, wrapped in protein, that infects other cells, usually very specific cells, repurposing the cell to create copies of the genetic material, wrapped in protein.