Is a wool-cashmere blend warmer than cotton?

Yes. Wool insulates even when damp and the cashmere adds loft, so it holds heat better than cotton at a similar weight. It is a cool-weather sweater, not a summer one.

How should I care for it?

Hand wash in cool water with a wool-safe detergent, or use a machine's wool cycle in a mesh bag. Dry flat and never tumble dry, which shrinks wool and roughens cashmere.

Blended knits usually pill where they rub, at the underarms and sides. A fabric comb removes the pills, and pilling settles after the first few wears.

Does it fit true to size?

The cut is not specified, so check the label's measurements against a sweater you already own. Wool blends have little stretch, so size up if you want room to layer.

Is it worth it over a pure-wool sweater?

The cashmere makes it softer against the skin than pure wool, which is the main reason to choose it. Pure wool is more durable and easier to wash, so pick based on comfort versus upkeep.