Is it permissible to use the "TikTok" application and put a "trending" song on a video for halal products for the purpose of marketing and increasing sales? And does the money generated from that become unlawful?

It is permissible to advertise halal products, as long as the advertisement does not contain anything forbidden. It is not permissible to include forbidden songs in advertisements to attract viewers and customers, even if this does not lead to thecribing the money earned from selling halal products; because advertising through such means is impermissible. What a Muslim acquires through permissible means is better for him, more beneficial, and more blessed.