What's your budget?
You can't really get a lens that's good for sport and lanscape, they are two completely different (and oppiste) types of photography. Sport requires a long, fast lens and landscape requires short and, well not slow but a fast lens isn't essential.
Anyway, here are some reccomendations for both:
Sport
High buget: Canon EF 70-200mm f/2.8 L IS or Canon EF 70-200mm f/4 L IS is cheaper. Without IS you can get a 70-200 f/4 for around £300, which is incredibally good value for money.
Low(er) buget: Canon 70-300mm f/4-5.6 IS
Landscape
High buget: Canon EF 14mm f/2.8 L Canon EF 16-35mm f/2.8 L
Low(er) buget: Canon EF-S 10-22mm f/3.5-4.5