Calls gain value as rates rise and puts lose it, because holding a call rather than the stock frees up cash that can earn interest. For a 30-day option the effect rounds to nothing. For a two-year leaps call it can be worth more than a point of implied-volatility.
Rho also drives one of the few rational reasons to exercise a put early: when interest earned on the strike proceeds exceeds the put's remaining extrinsic-value. In a zero-rate world that never happens; at 5% it happens regularly.
Example: the XYZ two-year $50 call has a rho of 0.62, meaning a one-point rise in rates adds about $62 per contract. The 30-day $50 call has a rho of 0.02, so the same move is worth $2. Same underlying, entirely different exposure.
Related: interest-rate-effect, leaps, early-exercise, option-pricing-inputs