Questions & Answers about Kafe ambiyansı sıcak ve keyifli.
The -ı is the third-person singular possessive suffix. In Turkish compound nouns, the head noun (the thing owned) carries a possessive ending while the modifier stays bare.
Example: ev kapısı (“house door”) is kapı + -sı, and kafe ambiyansı is ambiyans + -ı, meaning “the café’s ambiance.”
In simple present-tense predicates, Turkish drops the copula. You express “X is Y” by placing an adjective after the noun.
So Kafe ambiyansı sıcak ve keyifli literally reads “Café ambiance warm and pleasant,” i.e. “The café’s ambiance is warm and pleasant.”