I moved into an apartment in April now the landlord wants to raise my rent because of the taxes going up. Can they do that?

Where do you live... That sort of thing in the USA is regulated at the State Level. Meaning you can possibly have 50 different answers and all would be right for that area. 51 actually as the District of Columbia issues its own rules.

IF you have a year long lease the rent can not be changed until the year is up OR if you willingly renegotiate the lease. If you are a month-to-month renter the rent can be increased each month with a 30 day notice.

Basically ( leaving out rent control cities and areas)
If you have a lease, they can only raise the rent at the new lease date.

If you are on month to month, they can change the rent anytime with a 30 day notice.

And rent is based on profit, things like increase in property insurance, property tax increases, if they pay things like water or heat, increases of those costs.

I know locally here in Atlanta, water bills have almost doubled in some areas, so the landlord has little choice but to pass costs on.