Short answer: The next Halloween full moon will occur in 2038. Details:

• Halloween full moons are relatively rare, typically appearing roughly once every 18–19 years. After the 2020s, the next time a full moon falls on October 31 is anticipated to be in 2038 [web results context].
• The widely cited calculations and lunar calendars indicate that 2038 is the next year when October 31 aligns with a full moon, making Halloween a Boo Moon again [web results context].
• Until then, Halloween nights may feature other moon phases (e.g., first quarter or waxing gibbous) but not a full Moon peak on October 31 [web results context].

If you’d like, I can pull a couple of authoritative lunar calendars to confirm the exact full-moon timing for October 31, 2038 and provide a quick overview of nearby years with notable Halloween moon phases.