MyPlayground.swift

import SwiftUI
import Combine
import PlaygroundSupport

class SomeOtherObject: ObservableObject {
    var cancellable: AnyCancellable? = nil
    @Published var someValue = ""
    
    init() {
        self.cancellable = Timer.publish(every: 1, on: RunLoop.main, in: .default)
            .autoconnect()
            .sink { [weak self] _ in
                print("I'em still here")
                self?.someValue += "."
            }
    }
}

struct SomeView: View {
    @StateObject var otherObj = SomeOtherObject()
    
    @State var task: Task<(), Never>?
    
    var body: some View {
        Text("Hello, world!")
            .onReceive(otherObj.$someValue, perform: { _ in
                task?.cancel()
                
                task = Task {
                    // Do some sort of work here
                    print("Do work")
                    
                    if Task.isCancelled { return }
                    // Do some more work, update UI…
                }
            })
    }
}

PlaygroundPage.current.setLiveView(SomeView())