In terms of play-style, yeah, but I don't feel inclined at all to go and play TF2 if Overwatch is available.
They are still different games though.
Overwatch's characters have one weapon each (Torbjorn has two and D.Va also if you count the sidearm), 2 to 3 abilites with cooldowns, and one ultimate ability. Sounds a bit like Dota in first person, no?
Team Fortress 2's characters have three weapons and two tools each, plus you can get more to mix and match them.
So TF2 is its own twist on first person shooters while Overwatch is Dota in first person. I'm not implying the latter is a bad concept.