Quoting Dante’s Bones: How a Poet Invented Italy, page 247:

Mussolini’s dead body […] endured a level of abuse worthy of the poet’s law of contrapasso—fitting punishment for sin—under Italy’s new political order. After being mauled, shot repeatedly, and suspended from a steel girder like a butchered animal carcass, Mussolini’s corpse was buried in Milan’s Musocco cemetery.

Rejoicing antifascists danced on his grave, and one woman went so far as to urinate on it. On Easter morning of 1946, two days before the anniversary of Mussolini’s death, the hardcore fascist Domenico Leccisi and two accomplices dug up the body, wrapped it in canvas, and wheeled it out of the cemetery in a gravedigger’s cart.

Leccisi stored the decomposing cadaver in at least three different locations over the next year—first in the Valtellina, the area near the Swiss border where Pavolini had urged Mussolini to make a glorious last stand—before authorities recovered the body and brought it to Cerro Maggiore, a Franciscan convent outside Milan.

Mussolini’s corpse remained there for eleven years, its location known only to a few insiders. On August 30, 1957, an entourage of friars transferred the remains to the San Cassiano cemetery in Predappio, Mussolini’s hometown. The day after a memorial mass attended by his widow, Rachele, and a group of neofascists, he was buried in the family crypt.

Toward the end of the twentieth century, a period of historical revisionism in which fascist and partisan offenses too often received equal moral weight, Mussolini’s tomb welcomed around one hundred thousand visitors a year. Robust sales of his portrait and other souvenirs showed that the Duce’s body was “still selling briskly.”

(Emphasis added.)

Mussolini: The Last 600 Days of Il Duce, page 360:

The number of visitors to Mussolini’s tomb has more than doubled since the early 1990s, with about 70,000 pilgrims descending each year on Predappio, a little town of 6,000 population. Since 2000, a group of mostly young neo‐Fascists also has mounted a twenty‐four‐hour honor guard around Mussolini’s tomb.

Wearing long black capes and standing rigidly at attention for ten to twelve hours at a stretch, they represent a kind of secular priesthood. On major Mussolini anniversaries, marking his birth, rise to power and death, Fascists gather to sing party hymns and give the stiff‐armed Roman salute to their fallen hero.

Yesteryear the tomb attracted a substantial number of present‐day anticommunists.

That being said:

Ms Mussolini said that she agreed that attracting too many celebrating [neo]fascists was not a good thing. “The family doesn’t want a carnival atmosphere at the crypt,” she said.

(Source.)