If a unit can deepstrike, then this is literally mentioned in the codex entry of that unit (or the ability is given to them by a piece of wargear, e.g. jump packs). It's a special ability, units can't do this by default.
It is possible to create a chaos list in which all units can deepstrike, but no sane player would create such a list (no marines as troops...).
jwu
It is possible to create a chaos list in which all units can deepstrike, but no sane player would create such a list (no marines as troops...).
jwu