My fiance only has around 10% vision and doesn't know braille, tactile would definitely be the best option for him!

On my experience braille is a resource that should be used with care while adopting board games, mostly due to how much space it takes, and if you're talking about a deck of cards it may become hard to store/mix them. On the other hand it's very useful for exemple for small portions of the game, specially if it's a card that should stay hidden. One nice option would be having the names or codes of the cards in braille and a database accessible through the phone. I've played like this with a friend and it works wonders. You basicly have a text file on your phone, and when you need to take a card that you should keep in secret you read the code in it and search it on the text file. This could be used for your hidden objectives on a game like Dead of Winter or something like this for exemple. A friend of mine has suggested even adding QR codes to the cards so it would be even easier to access that. I haven't tried this yet. Maybe this could be a good option for those who are not familiar with braille, tho.

I am legally blind and don't read Braille. I can read larger or bold fonts just fine but most games have cards with either very small light font or they have words over a busy background that makes it impossible for me to read. You won't be able to please everyone in the blind community because we all have very different sight capabilities. But even something simple like high contrast cards would make gaming easier for me.

Some is fine, it depends on the person though

Unfortunately, braille literacy is not as good as general literacy. I am one of the rare few who is fluent in braille but you may want to consider implementing the braille code into your game because even though the literacy is bad, many people can still read braille. I hope this helps.

A lot of blind people just don't learn braille if they have either enough remaining vision or enough assistive technology that they don't feel they need to. With apps and audio books, etc. the need for braille is maybe not as great as it once was, outside of academics. Maybe they'll learn enough to decipher buttons on an elevator or something, but a lot of people (myself included) won't be anywhere near fluent.

I know of another game where blind and seeing people can play together. It's called Nyctophobia. Might be interesting for you to take a look and see what they used?

Although I know Braille berry well, I think your best bet is to go tactile. That way everyone is on an even playing field.
If including Braille, go with grade 1 that way everyone can play regardless of there Braille proficiency.