I was wondering the wright way to but a light in line with door bell. I will be doing most of my entertaining in basement and won't hear door bell so I want to put a light in when they ring door bell.

You could put a relay where your chime is(wire in parallel with chime). Contacts to connect to line already in chime box, and out of relay is lights switchleg.
Is it done in conduit? Does it have a transformer in wall behind Chime?

All wire can be easily excessed and the transformer is in rafter in basement which can be reached easily also.

U could get a wireless unit that sits on existing chime. The chime for wireless plugs into outlet.

When door bell rings, actives wireless and rings remote. Can be bought at most big box stores.

Chuck

Perfect, just connect like above and connect light after relay.
The relay allows a 120 volt(LIght/buzzer) to work with the chime.