Currently, only 3-player teams are possible in Apex Legends. However, a leak and a statement from the head of Respawn Entertainment give hope that solo and duo modes could soon be available in Apex Legends.
What is the current situation? Anyone who wants to play Apex Legends must necessarily compete in 3-player teams. Those who don’t have two friends are assigned random teammates (Randoms) by the game. Apex Legends is currently played exclusively in trios.
Thanks to pings and multiple respawn options, teamplay works surprisingly well even with such “Randoms”, but some players still prefer to go out as a lone wolf or in a duo.

This is not possible at the moment, but it could change soon.
Leak and Respawn Boss Provide Clues
What indicates new game modes: Data miners have discovered that the game’s code contains two entries titled “Solo-Mode” and “2-Man-Squads”.

These are clear indications of solo and duo game modes. However, such data mining findings should always be taken with caution. They could also be blatant fakes.
Has the head of Apex Legends hinted at new modes? Another vague hint comes from Vince Zampella, the head of the developer Respawn Entertainment.
A fan wrote to him, expressing that he really wants the solo mode in Apex Legends. For that, he would even come to the developers’ office and bring donuts – flavors according to the developers’ wishes.
The studio CEO immediately responded: “Any kind of donut?” Fans interpret this as a kind of commitment that there are indeed plans for solo and possibly duo modes in Apex.
Given that there is currently a fierce competition between Fortnite and Apex Legends, it is quite possible that Apex will make improvements soon, as Fortnite already has solo and duo modes.
However, it should be noted that some heroes, such as the tank Gibraltar and the healer Lifeline, make little sense in solo game modes. The strengths of some heroes would have to be adjusted for solo rounds.