You may have seen Luke List, Keegan Bradley, Chris Kirk, Colt Knost, Si Woo Kim or Patrick Cantlay with the M golf hat on. Some may think it is Mopar or another company. It is actually Travis Mathew which is getting into the golf industry in a big way lately. In 2018, we are seeing more Travis Mathew apparel than every before. The hats you are seeing on the PGA Tour probably look like this:
There are plenty of Travis Mathew golf shirts as well. If you are looking for a more slim fit, Travis Mathew is a great option. Those that wear Travis Mathew tend to wear Lululemon and Nike slim fit as well. I would suggest going and trying the shirts on because they do not fit everyone. I personally do not like the long sleeves of the short sleeve polo shirts.
Golf Galaxy now has a Travis Mathew section if you are looking to buy something with the M with the T in the middle.