A method performed by a first radio network node for handling mobility of a wireless device in a communication network, which communication network comprises partitioned sets of functionalities wherein each set of functionalities belongs to a network slice, which communication network comprises one or more Public Land Mobile Networks, PLMNs, with slices, wherein the one or more PLMNs are hosted in different Radio Access Networks, RAN, wherein each PLMN supports one or more network slices and at least one PLMN supports more than one network slices, where in the communication network a particular slice is indicated by a combination of PLMN identity, ID, with a slice ID, and wherein a set of functionalities is separated from other sets of functionalities out of a total set of functionalities in the communication network, the method comprising: - transmitting (1001, 1101, 1301), to a second radio network node in the communication network, a message comprising one or more combinations of PMN ID with slice ID that are supported by the first radio network node; - receiving (1102, 1102, 1302) from the second radio network node in the communication network, a response message comprising one or more combinations of PLMN ID with slice ID that are supported by the second radio network node; - obtaining (1003, 1103, 1303), during a connection setup of the wireless device to a network slice, an association indication comprising the slice ID that identifies the network slice that the wireless device is associated with, and; - receiving (1004, 1103a, 1105, 1304), as a response to the attachment of the wireless device, ∘ from the core network node, equivalent slice indication comprising one or more combinations of PLMN ID with slice ID, each combination identifying a network slice that is equivalent to the network slice that the wireless device is associated with; ∘ from the core network node or other radio network node slice allowance indication about slices allowed or not allowed to use for the wireless device; - determining (1004, 1105, 1304) to initiate a mobility procedure towards the second radio network node taking the information in the received response message the equivalent slice indication and the slice allowance indication into account, wherein determining to initiate the mobility procedure comprises: selecting (1005, 1105, 1305) measurements for making a mobility decision by matching the equivalent slice indication and the slice allowance indication against the information of the response message. - transmitting (1001, 1101, 1301), to a second radio network node in the communication network, a message comprising one or more combinations of PMN ID with slice ID that are supported by the first radio network node; - receiving (1102, 1102, 1302) from the second radio network node in the communication network, a response message comprising one or more combinations of PLMN ID with slice ID that are supported by the second radio network node; - obtaining (1003, 1103, 1303), during a connection setup of the wireless device to a network slice, an association indication comprising the slice ID that identifies the network slice that the wireless device is associated with, and; - receiving (1004, 1103a, 1105, 1304), as a response to the attachment of the wireless device, ∘ from the core network node, equivalent slice indication comprising one or more combinations of PLMN ID with slice ID, each combination identifying a network slice that is equivalent to the network slice that the wireless device is associated with; ∘ from the core network node or other radio network node slice allowance indication about slices allowed or not allowed to use for the wireless device; ∘ from the core network node, equivalent slice indication comprising one or more combinations of PLMN ID with slice ID, each combination identifying a network slice that is equivalent to the network slice that the wireless device is associated with; ∘ from the core network node or other radio network node slice allowance indication about slices allowed or not allowed to use for the wireless device; - determining (1004, 1105, 1304) to initiate a mobility procedure towards the second radio network node taking the information in the received response message the equivalent slice indication and the slice allowance indication into account, wherein determining to initiate the mobility procedure comprises: selecting (1005, 1105, 1305) measurements for making a mobility decision by matching the equivalent slice indication and the slice allowance indication against the information of the response message.