What did a tuxedo look like in the 1950?

In most regards, very much like it does now. The black jacket, satin lapels and pant leg stripe, black bow tie and cummerbund or vest, and patent leather shoes were all quite well established. A well-dressed man from 1950 could quite easily walk into a black-tie ball in 2008 without changing his clothes.

There have been some changes, most relatively minor. In the 50s, most lapels would have been either "peak" lapels, which are pointed, or "shawl" lapels, which are curved. Today, the most common lapel on tuxedos is the "notch" lapel, which is the same lapel as on a business suit.

In the 50s, most tuxedos would have had one button, with some having two. Today, the two-button variety is probably more common, with three- and four-button models sometimes seen.

Some tuxedos in the 50s would have been midnight blue, which has become much less common.

Tuxedo vests in the 50s would have been very low-cut, generally with three buttons. Most tuxedo vests sold and rented now are simply satin three-piece suit vests, high-cut and with five or six buttons. Some men wear black four-in-hand ties with tuxedos today, although this is obviously a bad idea.

So, minor changes aside, a man could wear a black jacket with peak or shawl lapels and a black bow tie and cummerbund and be welcomed by society in the 50s and the present.