Sombra is visiting his son, though no one is aware of his actions. As expected, the Crystal Ponies despise Sombra and Empress Cadence reluctantly had to exile Sombra from his former home. That didn't mean Sombra really listened to said order, using his old school magic is sneak into the Empire as he liked. His reason? To see his former Lover and their son, Olive Branch.
When he first learned about the child, he was ecstatic, still a bit evil at heart and wanting to take him 'home'. He chose not to since Golden Laurel was a loved one and he didn't want to hurt her anymore than he had already. So he chose to watch over his son from the shadows.
Sombra used to look upon his first born with disappointment and scorn, angry that his son was so weak of will. The darkness in his heart still yearned to rule the world, perhaps with his son by his side. But as time went on and he continued to visit, he started to grow fond of the meek stallion. He was the product of the love he used to hold in his heart and he portrayed that aspect perfectly. He was kind like his mother but with strong magic like himself. Olive was what his mother had hoped Sombra would become in their youth.
On the other side, Olive and Illusive are hanging out, though Luce can't help but wonder why he taste familial love in the air.