It looks like Sonic Frontiers will have DLC, based on this promo

Sega selling add-on content isn't too surprising, but we may have our first soft confirmation of Sonic Frontiers DLC.

Sonic Frontiers Official Website

Sonic Frontiers Could Be Getting DLC According To Taiwanese Promo Material

Sonic Frontiers release date and DLC 'listed by promo material

Sonic Frontiers' First Free Content Update Is Out This Week And Here's What's In It

SEGA: Sonic Frontiers sequel will benefit from larger budget, reiterates developing new DLC - My Nintendo News

Nintendo Download: Hanging on the Frontiers of Tomorrow

Sega Director Confirms Sonic Frontiers Is “Third Generation” Game - Gameranx

Sonic Frontiers: Paths Revisited Soundtrack Now Available Featuring Music From The DLC - GamerBraves

Sonic Frontiers Is Offering Free DLC Under One Condition

First look at Sonic Frontiers add ons : r/SonicTheHedgehog

Sonic Frontiers' to receive free 'Monster Hunter' DLC

Monster Hunter DLC coming to Sonic Frontiers for free on November 14th - My Nintendo News