From PSU:

It is important to know that not all vegetable varieties are suitable for seed saving. If the variety you want to save is a hybrid, seeds from that plant will not produce genetically true fruits. Most likely, the plant will produce a fruit that resembles one of the plants used to create that hybrid. To avoid this, choose heirloom varieties, ones that have been around since grandma's time or earlier. [...] Heirlooms will produce offspring that are identical to the parent.

https://extension.psu.edu/saving-seeds-from-your-garden