I trying as below but get empty data.

query.put("player_id", userName);
query.put("sort", "ascending");
query.put("cycle", "alltime");
query.put("team_instance_id","team_56cfed52cba05650015baaf3");

	query1.put("player_id", userName);
	try {
		pl = new Playlyfe(
			"YzgwM2I5ODAtNGE1Yi00ZTEyLWEzYTQtMTY2OTFjOGE2NmVh",
			"N2MzMjYxMDctNTY5Ny00NzM3LTk1OGMtN2E3ODFlMmFkNTViYzY4MzAwMTAtOTFhYS0xMWU1LTliODctMDczZDcwZGRmNGQw",
			null,
			"v2"
		);
			//ArrayList<String> actionList = (ArrayList<String>) pl.get ("/runtime/actions", query);
				Object obj = pl.get ("/runtime/leaderboards/cto_leaderboard", query);
				if(obj != null){
					modelMap.put("leaderBoard", obj);
					System.out.println(obj);
				}

Out Put:
{"data":[],"total":0}

You need to have players join the team first and your players should have some scores also. An then the team leaderboard will come with some data otherwise right now its gonna be empty until some one joins the team and also then need to play some actions.
You can also try all these api requests here https://dev.playlyfe.com/docs/api/v2/runtime.html first to make it easier than changing code always and checking whether it returns the right data.