What is Banquo rewarded with by the king?
Not much! Just praise, and a warm hug.
In Act 1, Scene 4, it's clear that both Banquo and Macbeth have shown bravery in the conflict, and King Duncan readily acknowledges that. First, the king confers the honorable title and position of "Thane of Cawdor" on Macbeth. It's a major reward: it raises Macbeth up in status.
Next, the king addresses Banquo. We might expect a similar reward to be given to him, since the king says:
That hast no less deserved, nor must be known
No less to have done so..."
"...let me infold theeAnd hold thee to my heart."
"But signs of nobleness, like stars, shall shineOn all deservers."