It is Chinese size and smaller than the USA size.
Please check the size carefully.
US Medium=China Large:Length:25.59"(65cm),Bust:37.80"(96cm),Shoulder:16.14"(41cm),Sleeve Length:24.41"(62cm)
US Large=China X-Large:Length:26.38"(67cm),Bust:39.37"(100cm),Shoulder:16.54"(42cm),Sleeve Length:24.80"(63cm)
US X-Large=China 2X-Large:Length:27.17"(69cm),Bust:40.94"(104cm),Shoulder:16.93"(43cm),Sleeve Length:25.20"(64cm)
SportsX Men Business Stylish Cardigan Knit Slim Fitting Blazer - QRRX1AWVO