Caraway seeds
Top 2 in Top 7 Best Substitutes for Cumin
The rectangular form and mustardy-brown color of cumin and caraway seeds make them look similar when placed side by side. This makes sense botanically because they are related. Caraway is a member of the parsley family, along with coriander and cumin. German cooking frequently uses ground or seed caraway.
Caraway is a great alternative even if it is a little milder than cumin. A good general rule is to use ground caraway in lieu of ground cumin and caraway seeds in place of cumin seeds. Replace half of the cumin with the caraway, then gradually increase the quantity to taste.