It's hard to even put into words what he's wearing there. Cutoff pants with leg warmers? Maybe he was trying to bring back long underwear with short shorts look? It's just too hard to explain, which is why we can just let the picture do the talking here.
Newton gave some clarification on what he was wearing, and it made a whole lot more sense after.
Per Jonathan Jones:
Cam Newton on his tights: "They're recovery stockings. If any day to recover, why not today"