Latest updates have all the content up-to-date. So if you download v0.14.1.5 you will get all the story available for now.
Widowmaker has her own route (two parts, but it's not finished, since we took a different approach and took our time with developing her not just as a character but as a person).
Mercy and Tracer are still in re-development. And with Kiriko we're still thinking how to kick-start her Route — with a full-fledged release or with a Story Update like Blaze, so we could flesh out her character.