Some already mentioned but…
The Wire – I love the expansion of the series to the system, the character development and the end of the last episode…
The Expanse – Sci fi done really well, amazing characters and in many ways as good as or better than the books (which is saying something as they are excellent too)
The West Wing – what politics should be. Feels dated in parts, but also prophetic
Dark – I know it is in German and is really tough to follow if you dont pay attention, but boy is it worth it. Ties up all the loose ends well, which TV can often fail to do).
Band of Brothers – just amazing and terrifying TV. Again the book is well worth a read