There
is a distinct accent of Canadian English spoken West of Quebec (English in Quebec and through Atlantic Canada has many variants); it's a bit difficult for an untrained ear to distinguish it from "accentless" American English, but it's fairly easy to detect once you know what to listen for. Canadian raising is the big tip off - for a Canadian, the vowel sound in "lout" is different from the vowel sound in "loud," ditto "writer" and "rider." This is where the whole "aboot" thing comes from.
Accents aren't stable; they go through their own internal sound changes over time, their boundaries shift, some die out and others are born. The Southern US accent, for example, has changed dramatically over the past few generations. Almost every young person in the American South speaks with a rhotic accent these days, despite a lingering stereotype of a non-rhotic drawl. You're not going to hear the Southern accent if that's the cue you're looking for. If you're looking for the pin/pen merger (another distinctive feature of the Southern US accent), you'll hear it loud and clear. It's even spreading North, further and further into the formerly "neutral American" Midwest.
In Canada, we've seen the emergence of a distinct sound change over the past several decades called the Canadian Shift. From the research I've read on it (and research into Canadian English phonology is pretty scanty), it seems to have started in or near Toronto sometime in the first half of the 20th Century. Older men may not exhibit this vowel shift at all, while it is nearly universally complete in young women (at least in Toronto, the shift has been moving at different paces through Ontario and into Western Canada). In broad terms, this shift has seen some vowels move lower and further back. Our neighbours directly across the border in the Northern Cities have seen their vowels move in the opposite direction, so we're actually becoming more distinct from each other here. That said, a (likely) unrelated but similar shift has occurred in California, which is reflected in the popular culture we consume here; the American English we hear on TV and in the movies sounds more "like us" than what you'd hear on the streets of Buffalo or Rochester.
I think, out of necessity, Torontonians tend to filter out a lot of these small differences in everyday life. Most of the people who live here aren't from here (they're either immigrants or transplants from other parts of the country). We've all learned how to cut through a thick accent - we've all had to - and in the process we've lost our ear for detecting subtle cues and the like.
All of that said, I believe a distinct Toronto accent has begun to emerge in Millennials, but I wouldn't know exactly how to describe it. It seems to come out strongly in me when I've had a few drinks (I get "Where's your accent from?" fairly often when I'm at bars out of town, especially in the US). The people in this video kind of come close to what I'm talking about:
https://www.youtube.com/watch?v=ZvHn0UpA1XU