Rust has trait inheritance, it looks like this:
pub trait A {}
pub trait B: A {}
However, this does not mean that if a type extends B it will automatically extends A; trait inheritance is just a way to specify requirements, that is, trait B: A means that we can know that if some type T implements B, it also necessarily implements A.
Naturally, you can use this to specify that a trait extends a combination of other traits:
pub trait Something: Clone + Send + WhateverOtherTrait {}
Again, it just means that every type which implements Something must also implement Clone, Send and WhateverOtherTrait.
Implementing multiple traits at the same time is not possible. I think this is because in the vast majority of situations traits are sufficiently different so such implementation won't work anyway.