Usually, most Pansexuals don’t have gender as a factor on their attraction, many Bisexuals do. Bisexual has a more ample definition.

There are people who date multiple but not all genders for example, but there’s a lot overlap between both communities. And there’s also more plurisexualities (the + in Bi+, like polisexuality and omnisexuality) who also overlap. People sometimes use a specific one to share details about they experience their sexuality.

There’s nothing wrong with using either one or all, but we need to respect everyone’s choice about how they refer to their own sexuality.